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SuzukiSavage.com
/cgi-bin/YaBB.pl General Category >> Rubber Side Down! >> Cam chain tensioner revisited /cgi-bin/YaBB.pl?num=1463512512 Message started by Armen on 05/17/16 at 12:15:12 |
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Title: Cam chain tensioner revisited Post by Armen on 05/17/16 at 12:15:12 I've been reading the stuff on the cam chain tensioner, and seen the mod offered to extend the tensioner arm for more travel. Makes me think about the root of the problem. Honestly, I don't see that many cam chains on other bikes stretch out that much. And extending the arm just means that the chain is really stretched out. Which isn't great for the sprockets. Looking at the stock tensioner, it has a ratchet on it so that the arm cannot retract once it extends. So, when the cylinder is cold, the arm extends. The the engine heats up and the cylinder grows. But the chain doesn't. So maybe the grief here is that the tensioner is stretching the chain? When we raced an SR500 in AHRMA I modified the original automatic tensioner to semi-automatic. I'd allow a little slack when the engine was cold, then when it heated up and the cylinder grew, the chain basically ran with no slack, but no tension. Thinking about doing the same thing on the Savage. Downside is that it would mean pulling the clutch cover to adjust periodically. Waddayatink? -Armen |
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Title: Re: Cam chain tensioner revisited Post by Dave on 05/17/16 at 12:20:57 I have been considering this as well. My bike is a Cafe Conversion, and the pegs are not in the way to remove the clutch cover. I would only need to remove the exhaust system (3 bolts), and then remove the cover. It could be as simple as taking the spring out of the tensioner and moving it manually. The last bike I worked on, I put a very weak spring in the tensioner, and MMRanch did the same a while back. |
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Title: Re: Cam chain tensioner revisited Post by norm92de on 05/17/16 at 12:38:55 I have been thinking about this also and am very interested in batman's solution, i.e. take out the pawl. It sounds like lunacy but he swears that he has had no problems in a few thousand miles. I am very nervous about it but the proof is in the pudding. (haven't done it yet) :) I have also thought about filing every other tooth off the ratchet which would possibly halve the wear cycle? Clearly the cam chain spends a lot of its time over tensioned. |
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Title: Re: Cam chain tensioner revisited Post by Dave on 05/17/16 at 12:43:50 2F2E332C78732524410 wrote:
That is the one thing I know won't work. The pawl engages several teeth on the plunger at once. If you remove every other tooth you won't change the travel - you will only succeed in having half as many teeth engaged to resist the forces. |
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Title: Re: Cam chain tensioner revisited Post by verslagen1 on 05/17/16 at 12:56:53 This would solve your adjustment issue... http://suzukisavage.com/yabb2.2/Attachments/wire_form.jpg http://suzukisavage.com/yabb2.2/Attachments/insert7.jpg http://suzukisavage.com/cgi-bin/YaBB.pl?num=1448856365 |
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Title: Re: Cam chain tensioner revisited Post by norm92de on 05/17/16 at 13:04:03 Dave, I didn't know that. I thought only one tooth at a time engaged. Another thought, with your a rigid tensioner? How many miles would it take for the chain to wear down enough to be "too loose"? Any guesses? |
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Title: Re: Cam chain tensioner revisited Post by Dave on 05/17/16 at 13:16:14 I have no idea how fast the adjustment occurs with a stock tensioner vs. how fast the wear "needs" to be adjusted. When I last had my bike apart it was at 1,200 miles, and the tensioner measured 14mm. I now have 7,000 miles on it and plan on taking it apart in a month or so....and I can measure it again and then convert it to manual. I also don't know what "too loose" will be....maybe it doesn't need to be adjusted every tooth like the stock system does automatically. I think you just ride....and maybe once a year make an adjustment until you get a feel for what is required. After the first year you would know how much wear occurred by measuring the extension and recording the mileage before you remove the spring, then take the spring out and ride......next winter you remove the side cover, look at the tensioner and give it a small shove and see where the piston ends up (measure), then take the tensioner off, install the stock spring and rotate the engine over several times...then measure again (this will give you an idea how accurate your "shove" was. Then take the spring back out and shove the plunger to the dimension that you measured when you put the spring back in. Another option is to do what Verslagen is suggesting....or maybe a small cable/wire looked into the oil fill port. |
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Title: Re: Cam chain tensioner revisited Post by verslagen1 on 05/17/16 at 13:26:28 42716E666D030 wrote:
This would be an issue with roller chain, but is not an issue with our silent chain. Our sprocket is more of a gear and the chain just has slots that engage with the gear. A loose chain will just float over the teeth engaging with the same area it always engages with. Key issue to be aware of is the pin wear. Once that gets thin enough to double shear... look out. Chain stretch of .060" across of I don't know how many pins ain't a whole lot of wear. |
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Title: Re: Cam chain tensioner revisited Post by norm92de on 05/17/16 at 13:28:50 I like versys idea. As long as I don't drop the thing down in the engine :P |
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Title: Re: Cam chain tensioner revisited Post by Armen on 05/17/16 at 13:29:56 Another option is to put a rod in the center of the spring/plunger and lose the ratchet. A bit of trial and error and you get the right amount of slack. We do a similar thing on the rebound block on Smith and Wesson revolvers to limit trigger over-travel. When the chain becomes a bit loose, just shim up the rod or swap to a longer rod. I bought a new cam chain, so this would be the time to do it ;) |
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Title: Re: Cam chain tensioner revisited Post by norm92de on 05/17/16 at 13:33:20 I think I am going to get pretty rapid chain wear since my riding is always 50/80 miles at a time, Never more. :'( |
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Title: Re: Cam chain tensioner revisited Post by verslagen1 on 05/17/16 at 13:34:46 1E25283F2E22393F242C213E4D0 wrote:
The oil diverter in front of the oil fill port is perfect for keeping something out of the chain. However, a cable I wouldn't want to use as it might flex enough to get eaten by the chain. Maybe a plate retained by the plunger bolt would work but still seems a risk to me. Insert the wire, give it a tug, and remove it. Nothing to get caught up in anything. |
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Title: Re: Cam chain tensioner revisited Post by norm92de on 05/17/16 at 13:36:51 armen, I thought off that. It becomes a completely manual adjuster. With the normal spring tension. And so easy to accomplish. |
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Title: Re: Cam chain tensioner revisited Post by norm92de on 05/17/16 at 13:39:51 Since several of us are online. Does batman's idea seem too cavalier? It is so simple. |
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Title: Re: Cam chain tensioner revisited Post by Serowbot on 05/17/16 at 14:03:14 I think the tensioner starts out 12 to 14mm extended. The factory plunger was just made a bit too short to allow for much stretch at all. With Versy's extension and the added safety of the pinned slot, I'm pretty comfortable. I don't believe we've ever had a chain stretch beyond that point,... and I don't recall a chain breaking either... Anybody recall a broken chain?... I may be wrong. :-? |
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Title: Re: Cam chain tensioner revisited Post by Dave on 05/17/16 at 14:13:50 50514C53070C5A5B3E0 wrote:
That method scares me....every tensioner in every cam chain in every engine I know about - is either locked in place (manual), or has a tensioner pawl that prevents the plunger from moving backwards........or has a hydraulic "shock" system that restricts sudden movements backwards. Allowing the tensioner to flop around unrestricted - that just doesn't seem like a good idea to me. |
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Title: Re: Cam chain tensioner revisited Post by norm92de on 05/17/16 at 14:20:50 Has anybody tried drilling a 'peephole' in the oil deflector. You could then eyeball the tensioner? Could you see enough? |
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Title: Re: Cam chain tensioner revisited Post by norm92de on 05/17/16 at 14:25:05 I hear you Dave. Every engine! Playing the devils advocate. What do you think is a worst case scenario? |
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Title: Re: Cam chain tensioner revisited Post by gizzo on 05/17/16 at 14:30:13 I had thought of boring a hole in the side cover and fitting a big hydraulic tank sightglass to observe the chain, but can't really be bothered. Don't know whether that would be any use. FWIW, the Honda cx500 has a manual chain tensioner that your supposed to adjust each time the valve clearances are done. It's easy and the side cover doesn't have to come off, though. It's often, is all. |
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Title: Re: Cam chain tensioner revisited Post by verslagen1 on 05/17/16 at 14:35:09 Batman's mod you have to take on blind faith. :-? and no sonar to sense what's going on either. This works for Batman, but will it work for you? zuki engineers put that pawl in there for a reason, maybe it went out with the 4 speed, maybe it didn't. |
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Title: Re: Cam chain tensioner revisited Post by verslagen1 on 05/17/16 at 14:43:15 3422352830252833470 wrote:
I believe we've had a couple of broken chains. Remember Yonuh Adisi? |
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Title: Re: Cam chain tensioner revisited Post by norm92de on 05/17/16 at 16:10:01 One thing that occurs to me is that if the cam chain tension is high, so is the load on the cam bearings in the head. I hate it when that happens. :'( |
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Title: Re: Cam chain tensioner revisited Post by norm92de on 05/17/16 at 16:14:04 Talking about 5th gear I sure wish it was 5 and a half! ;) |
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Title: Re: Cam chain tensioner revisited Post by verslagen1 on 05/17/16 at 19:42:41 norm... slow down yer starting to studder. |
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Title: Re: Cam chain tensioner revisited Post by Ruttly on 05/17/16 at 19:57:33 Loose the ratchet and the spring , use a small rubber cup like one on a wheel cylinder from a car brake system and plumb a tiny hose from a oil galley to it and use oil pressure for suppling tension, still would need a light spring for tension when engine isn't running. Honda 90s use the same basic idea ! That my extreme remedy and my 2 cents worth ! |
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Title: Re: Cam chain tensioner revisited Post by Art Webb on 05/17/16 at 20:55:10 2524392672792F2E4B0 wrote:
That's sort of the problem, it's really more like 4th and a half than 5th |
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Title: Re: Cam chain tensioner revisited Post by batman on 05/18/16 at 21:29:19 dave ,dave,dave,...you trust the springs in your tensioner to be strong enough to push the plunger out but not enough to hold it there? you trust that the tiny little spring and tiny little paw to hold there ? I believe my large spring holds it in tension at all times,as for flopping around I have no indication,by way of sound or it,s performance that it is moving at all. IM a bit of a wicker and ride 60 on two lane mt. roads 70 on four lane div. highways,usually with my gal, total of 345lbs onboard. |
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Title: Re: Cam chain tensioner revisited Post by batman on 05/18/16 at 21:36:42 maybe the Suzuki eng. designed the tensioner to fail ! so you would buy the next larger bike ,and the next beginner couldn,t buy yours ! |
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Title: Re: Cam chain tensioner revisited Post by batman on 05/18/16 at 23:13:17 Dave gave us a picture of a Porsche tensioner,that restricts movement using hydraulic pressure which on first attempt failed,I'm waiting for my tensioner spring to fail ,but I'm a patient man. and thinking about the Porsche boxer engine a 180 degree flat six with duel over head cams their need for heavy duty tensioner on a chain that might be 8 feet long might be over kill for our bikes. |
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Title: Re: Cam chain tensioner revisited Post by Garry on 05/19/16 at 02:36:39 The cam chain tensioner on our bikes is connected to the guide at the bottom of the guide which may be leveraging the guide to flex in the centre and straighten slightly allowing the chain to lose tension and causing the tensioner to advance unnecessarily? Most other cam chain tensioners exert pressure on the centre of the guide which I would think is the most effective place to do it. There is nothing we can do about the placement of the tensioner but there is probably something we could do regarding strengthening the guide to limit flexing? Just a thought! :o |
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Title: Re: Cam chain tensioner revisited Post by Armen on 05/19/16 at 02:43:54 As to the question of the spring tension alone holding the tensioner blade: What happens is that as the motor is running, the chain tries to become a circle on the unloaded side. The front part is drawn tight by the crank pulling against the valve spring tension. The back of the chain is thrown off the crank sprocket and tries (successfully) to push back the spring tensioner. The pawl is to stop this from happening. My issue is that the pawl keeps the tensioner locked at a place which might be correct tension with a cold motor, but probably too tight when the motor heats up and the cylinder grows. If you have a bike with a center stand, get the bike on the stand, put it in gear and rev it up. You'll see the top (loaded) part of the chain tight and the bottom flailing. -Armen |
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Title: Re: Cam chain tensioner revisited Post by Garry on 05/19/16 at 02:51:12 Yes good point. Hadn't thought of that. So it's really the fact that the tensioner over tightens the chain due to expansion and contraction of the height of the motor with temperature change. If that's correct and it seems logical, the only way to make the system effective would be to make the tensioner manual and adjust it at each service? This would prevent the cyclical temperature changes from allowing the chain being regularly over tightened. Would reducing the strength of the spring in the tensioner help? |
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Title: Re: Cam chain tensioner revisited Post by Dave on 05/19/16 at 03:39:31 3437223B3738626E560 wrote:
The chains on the Porsche engine (1 left, 1 right) are a similar length to our chain. The chain goes from the intermediate shaft to the overhead cam.....the only big difference is that the chain is driving a longer cam and works 3 cylinders instead of just one. The Porsche cam chain is a double roller chain rather than the silent chain used on the Savage. I was looking at images of tensioners to see how others are made, and I found a tensioner for Honda cars, and it commented on the tensioner issue they have. Evidently the problem is that when the valve is closing - the spring pressure pushes on the cam lobe and drives the cam forward slightly, and this can allow the valve to close too fast and the valve hits hits the seat too hard. I don't know that this occurs on the Savage, as the Honda car most likely doesn't use rocker arms and it probably has an intake and exhaust cam....so the design is much different. I hope you do have success, and that it works out fine. I am not yet convinced that the removal of the pawl is a good thing, and that the forum members should follow your method. Only time will tell if you have found something more durable than what the stock tensioner provides. |
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Title: Re: Cam chain tensioner revisited Post by Dave on 05/19/16 at 03:57:05 1519101916200 wrote:
I will be making that change in a week or so. I will take the side cover off, measure the extension of the plunger, then take the internal spring out and extend the plunger to match the measurement that I got before I took the plunger spring out. The pawl will keep the plunger from moving back in.....the plunger will not have any spring to move it out. Another option would be to make a way to lock the pawl in place, and just leave the plunger spring in the tensioner. That way you could unlock the pawl and allow the spring to establish a new setting by turning the engine over a bit....then lock the pawl to prevent any additional movement. |
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Title: Re: Cam chain tensioner revisited Post by Garry on 05/19/16 at 04:22:49 So you will effectively have a manual camchain adjuster. With no spring to move it out you will need to do that manually from time to time. Your second idea about leaving the spring in place and working out some method for locking the plunger in place is probably safer. This is what a lot of early Jap bikes used and it was very effective |
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Title: Re: Cam chain tensioner revisited Post by Armen on 05/19/16 at 07:09:49 Yup. Pretty much what I had in mind. Just have to pop off the clutch cover and the tensioner. -Armen |
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Title: Re: Cam chain tensioner revisited Post by batman on 05/19/16 at 09:22:16 dave ,you said on the Honda car the cam was advanced and closed to early,but as our chains wear our cam timing as compared to the crank is more and more retarded, if so the exhaust valves and inlet valves may be seating at their original timing,on my bike |
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Title: Re: Cam chain tensioner revisited Post by Dave on 05/19/16 at 09:56:16 2B283D2428277D71490 wrote:
The point was not the cam being advance.....the point is that without a pawl or something to keep the valve spring from driving the cam forward.......the cam can move and create slack in the front section of chain and tension in the back portion. On the Honda car it is the exhaust cam that is nearest the backside of the cam chain and the tensioner, and the when it advances the small section of the chain between the 2 cams becomes loose.....this apparently is a big problem for the Honda during start up when there is no oil pressure in the tensioner. And it becomes more of a problem for the Honda when bigger cams and stronger valve springs are used, and the ratchet in the stock tensioner can be broken. http://cms.skunk2.com/id/389/K-Series-Tensioners-The-Solution/ While I realize the movement in the Savage engine is not likely to be an issue at higher rpm that exceeds the ability of the valve spring to accelerate the cam forward - it may be an issue at lower rpm, idle, start up, or when shutting the engine off - when the valve springs have a chance to move the cam faster than the crankshaft is turning the cam. In checking your other post, it appears you have had the pawl spring out for about 6,000 miles.......you need to get a lot more miles on your bike before it is out of the trial/testing phase.....and proven to be a reliable solution to the tensioner/cam chain issue on the Savage. |
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Title: Re: Cam chain tensioner revisited Post by norm92de on 05/19/16 at 10:14:14 What I like is that batman is our guinea pig so to speak. His bravery may yield the best solution. My thoughts are, as somebody suggested, to put a solid rod inside the spring and remove the pawl. It would need to be just the right length so that the tension is optimal, whatever that is, so that as the engine expands the tension is not too tight. It couldn't be any worse that what the pawl does. |
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Title: Re: Cam chain tensioner revisited Post by Dave on 05/19/16 at 10:18:51 62637E61353E68690C0 wrote:
The solid road isn't really required....you just remove the plunger spring, and then extend the plunger to the length you want....the pawl will hold the plunger wherever you left it. (If the plunger does happen to move farther out without a spring inside....chances are it need to be adjusted anyhow). I do hope that Batman has success with his approach - I am just a bit too conservative to take an approach that is not proven. Having a cam chain break while I am leaned over in sharp curve is not my idea of "Adventure Tourism". |
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Title: Re: Cam chain tensioner revisited Post by batman on 05/19/16 at 10:19:58 I'm sorry if I offended anyone with this topic ,I really just threw it out there . I think it works for me and will report back this fall when I open the motor up . I don't need anyone to follow my lead ,I did want to start a conversation about what has always been a pain in our butts. I think we have brought much great info to light . I would like to thank everyone ! Over and out,batman.... |
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Title: Re: Cam chain tensioner revisited Post by Dave on 05/19/16 at 10:23:12 I am not offended....anybody else? :-? |
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Title: Re: Cam chain tensioner revisited Post by norm92de on 05/19/16 at 10:23:18 Good point Dave. With the spring removed as long as the plunger stays put, and it should, no problem. |
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Title: Re: Cam chain tensioner revisited Post by norm92de on 05/19/16 at 10:25:40 Not me either. The more we throw this around the better :) |
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Title: Re: Cam chain tensioner revisited Post by justin_o_guy2 on 05/19/16 at 10:34:58 I think it's a grand and potentially Very exciting experiment. |
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Title: Re: Cam chain tensioner revisited Post by Art Webb on 05/20/16 at 08:34:02 I don't think anyone is offended, I think there's a lively intellectual debate going, the VERY healthy kind, and some are quite hopeful while others are sceptical for one group to remain silent while the other speaks leads to an intellectual echo chamber, where fresh thoughts may be stifled or left uncritically examined I think this is a great discussion |
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Title: Re: Cam chain tensioner revisited Post by norm92de on 05/20/16 at 10:29:48 Talking about cam chains in general. What do other bikes get out of their cam chains mileage wise. I have never owned a bike long enough to need to replace a chain. CB77/Yamaha XS650/Suzuki GS650 among others. What is the consensus? |
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Title: Re: Cam chain tensioner revisited Post by justin_o_guy2 on 05/20/16 at 10:46:47 We've seen very short lived and a coupla chains went twice the average. I Think a couple gave out around six thousand , and a couple made near thirty,but, not sure... Getting around twelve,maybe sooner, time to be listening,for sure, especially if you tend to make fifteen mile trips. |
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Title: Re: Cam chain tensioner revisited Post by Meme on 05/20/16 at 11:40:09 0D0C110E5A510706630 wrote:
I haven't had any problems with the chain on my Savage yet, but from what I read, they go out way too fast. I've never had to do anything but adjust the cam chain tension on any of my bikes. I had a XS1100S with almost 100,000 miles on it that didn't get a new chain. I think the OPs suggestion that the tensioner makes the cam chain too tight is probably correct. |
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Title: Re: Cam chain tensioner revisited Post by Armen on 05/20/16 at 11:55:31 From what I've seen, wear depends on a few things. Older BMW Airheads had massive flywheels, and double row timing chains. Not unusual on a highway/touring bike to see many tens of thousands of miles on a chain before it gave grief. As time went on, the flywheels got lighter, and in '79 they went to a single row timing chain. On my '79 R65, which has a light flywheel and single row chain, I replaced the timing chain 3 times in 45K miles. Then again, I commuted into Manhattan, and rode it like I stole it. Certainly revving the nuts off a motor wears out the whirly bits faster :o -Armen |
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Title: Re: Cam chain tensioner revisited Post by batman on 05/20/16 at 11:56:42 My aim was not to offend, but when I start a reply with Dave dave, dave,....he or others might not understand that as just my sense of humor. My thought is laughing is better than crying ,I like to tease a bit but this may not be evident when read on the small screen. |
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Title: Re: Cam chain tensioner revisited Post by Dave on 05/20/16 at 15:50:20 There is a fellow on the Ninja 250 forum that had about 80,000 miles on his bike and it was running strong - but the cam chain had grown longer than the cam chain tensioner system could handle. Replacing the chain in that bike requires a complete tear down of the engine - as the cam chain is in the middle of the crank and has to slide over the crank to be removed. It was cheaper and easier for him to just buy a low mileage used engine than try to rebuild his original engine. |
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Title: Re: Cam chain tensioner revisited Post by norm92de on 05/20/16 at 17:05:55 Why wouldn't it be possible to simply break the chain and feed in a new one? Surely it is possible to re-rivet a cam chain??? |
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Title: Re: Cam chain tensioner revisited Post by batman on 05/21/16 at 07:40:24 The 250's being starter bikes for the rice rocket set are pretty common on places like fleabay. Reassembling the new chain and having it as strong as it was would be your problem,and these bikes have redlines nearly twice ours |
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Title: Re: Cam chain tensioner revisited Post by justin_o_guy2 on 05/21/16 at 08:34:10 4948554A1E154342270 wrote:
The problem is obvious, the simple solution, as you say, build a chain with a master link. I'm pretty sure that since the problem exists and is obvious but nobody offers the replacement chain in any form other than one piece. I don't really see why not either. I know what hazards a master link cause, but I don't see why it wouldn't work. The thing is, it's a built in weak spot on an already stressed, CRITICAL area. The liability for the manufacturer could be considerable. The scene Long, decreasing radius sweeper, guy, tucking tighter, dropping gears, matching revs, and the cam chain parts, engine causes the rear tire to slide out, he gets hurt, Then, figure out how the weight difference in the master link affects the chain, zooming around gears, sliding up and down guides, And, no, nobody has what it takes to join a chain that is installed. Nobody can access it and pound a peined end rivet in. If someone can, it's a rare bird. I'm not that bird. |
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Title: Re: Cam chain tensioner revisited Post by batman on 05/22/16 at 20:45:25 JOG ,I agree I dont think it would be possible to reconnect the chain and be assured it would stay together.(oops) Many seem to think my removing the spring in the paw to be radical,and that the chain tries to go oval on the back side. Let's say it does,but the pressure is spread against the entire guide ,the spring inside is compressed and pushes back harder, does it move yes,but how much. We need superman's x-ray vision for this one.but I do know this, when my bike cools down the paw is not there to stretch the s**t out my chain! |
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Title: Re: Cam chain tensioner revisited Post by justin_o_guy2 on 05/22/16 at 20:52:42 I'm 100% behind the test. Glad someone is taking that bull by the horns. |
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Title: Re: Cam chain tensioner revisited Post by Armen on 05/23/16 at 02:48:13 I think the combination would be to remove the pawl, leave the spring, and set up a block to limit the amount the plunger can go back (slack). I'll try to get that done this week. If I was really enthusiastic, I'd measure the height of the cylinder at room temperature, then put it in the over at maybe 220F, and measure the stretch, and use that figure to determine how much play the tensioner needs. Or maybe just look up the amount that aluminum grows in that temperature range. -Armen |
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Title: Re: Cam chain tensioner revisited Post by batman on 05/23/16 at 07:13:08 armen,i think your on track,this may be really off the wall,you could use a small hardwood dowel (sealed with epoxy?) inside the spring 1or2mm. shorter than the space behind the plunger. this may sound weird unless you are aware that pound for pound wood is stronger than steel,and the compression strength of hardwood can be as high as 60,000psi.Being wood it couldn't damage any of the metal parts of the tensioner,and would afford protection if the paw were to fail (MacGyer at it again!) |
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Title: Re: Cam chain tensioner revisited Post by Armen on 05/23/16 at 07:15:59 Batmen, I was going to use a length of steel round rod inside the spring. Wood may be stronger, but it doesn't like to be soaked in hot oil. Kinda doubt the steel in compression will have any strength issues ;) thanks, -Armen |
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Title: Re: Cam chain tensioner revisited Post by batman on 05/23/16 at 07:17:54 yes the oil might be the biggest problem |
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Title: Re: Cam chain tensioner revisited Post by Dave on 05/23/16 at 07:21:55 No one has ever had a tensioner break the pawl or the teeth...if they did it has never been reported on this forum that I am aware of. I suppose that the pawl/teeth could be broken if the adjuster wasn't moved for an extended period, and a lot of slack built up and it allowed the chain to "snap" backwards. I believe the relatively flimsy offset metal bracket on the guide would fail before the teeth on the pawl would break. |
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Title: Re: Cam chain tensioner revisited Post by Armen on 05/23/16 at 07:26:19 The pawl breaking isn't the issue as I see it. I'm removing the pawl so that the chain isn't being held taught as the cylinder expands. All I'll do is yank the side cover every now and then and check the chain slack. If it is to slack, I'll either make a longer rod to fit inside the tensioner spring, or shim up the dowel. Once I get to it, I'll take some pics. Just read the thing on the list about tarting up the forks. Am chasing down a lower tree and gassing up the milling machine and lathe ;) -Armen |
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Title: Re: Cam chain tensioner revisited Post by Dave on 05/23/16 at 07:30:34 053629212A440 wrote:
That could be a workable solution...the plug would just prevent the tensioner from allowing too much slack. When you take your engine apart, just measure the extension of the plunger, and make your dowel so that it allows just a tad less room and the plunger can move back only slightly below what you measured. I like this idea more than any other I have seen. It does require occasional attention to build a new rod - but how often we really don't know until someone road tests it for 5,000 miles or so! |
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Title: Re: Cam chain tensioner revisited Post by batman on 05/23/16 at 09:43:47 why make a new rod each time?Use a threaded rod hex coupling nut(3/8 16),turn/file it round to a light press fit into the base of the plunger, cut it to the length that suits you add a bolt ,nut, star lock washer and you can adjust anytime to any length your heart desires.(there goes that #$$%%$#@%^& MacGyver again) |
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Title: Re: Cam chain tensioner revisited Post by Dave on 05/23/16 at 09:54:51 3231243D313E6468500 wrote:
If you did that.....where would you put the spring? Armen was going to put a rod cut to length in the ID of the spring inside the plunger......at least that is what I understood from his post. |
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Title: Re: Cam chain tensioner revisited Post by batman on 05/23/16 at 09:58:03 Oops I was thinking about your method of just using the paw and what you might do for a little insurance. |
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Title: Re: Cam chain tensioner revisited Post by norm92de on 05/23/16 at 10:39:19 What would happen if you removed the spring just leaving the pawl? You could push the rear guide up to the chain each time. The rear guide wouldn't go anywhere would it. Then it might be possible to use Versys bent rod to pull the rear guide up a notch each time. |
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Title: Re: Cam chain tensioner revisited Post by Dave on 05/23/16 at 11:00:11 7879647B2F247273160 wrote:
Personally I like that idea....and it would be really nice if you could figure out a way to just leave something in place to pull....a permanent bent lever (or cable) of some sort. |
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Title: Re: Cam chain tensioner revisited Post by norm92de on 05/23/16 at 11:19:17 Does the spring tension have a function or will the rear guide do its job without the spring? A new design attachment bolt with something to hook on to might work. Or something attached to the plunger? versy's mod will give us a hole to work with, either before or after. |
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Title: Re: Cam chain tensioner revisited Post by Dave on 05/23/16 at 11:39:28 40415C43171C4A4B2E0 wrote:
That is an interesting question. In the stock application the spring pushes out the plunger to a proper "preload"....once the engine is running the pawl controls what is going on - but that same pawl has no ability to relieve tension as the engine warms up and expands. If you eliminate the pawl and insert your spacer...likely the spring would have little or no function. I don't know what would be a proper amount of spring tension to apply when the pawl is gone. The harder you push on the guide....the faster the guide and chain will wear. |
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Title: Re: Cam chain tensioner revisited Post by Armen on 05/23/16 at 11:43:36 Go back to the earlier description. The idea is to set up the tensioner with enough slack to allow for the cylinder expansion. Leave the spring in there to take up the slack until the cylinder heats up. No pawl. This is kinda turing into teenage sex-months of talking, a few seconds of activity, and months of exaggerating afterwards ;D -Armen |
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Title: Re: Cam chain tensioner revisited Post by norm92de on 05/23/16 at 11:46:50 Another thought. Are we correct in assuming that the relatively short life of the chain is due to over tension due to expansion. Or some other factor. |
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Title: Re: Cam chain tensioner revisited Post by Armen on 05/23/16 at 11:52:28 My thought was that the bike has all the right ingredients for a long happy chain life: No power, no crank acceleration, heavy crank and flywheel to even out the power pulses, mild valve springs, and so on. And a Hy-Vo chain. Made me start scratching my head and looking for a better answer. Not sure if I'm right, just makes sense. |
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Title: Re: Cam chain tensioner revisited Post by norm92de on 05/23/16 at 12:10:00 The tensioner does have poor mechanical advantage located low down on the chain compared to most engines where they are located more or less in the middle of the chain throw. Maybe this is why the spring is so strong. |
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Title: Re: Cam chain tensioner revisited Post by justin_o_guy2 on 05/23/16 at 12:20:46 The pawl latching into the teeth on the tensioner tube is what contains the chains pressure on the tensioner. The spring forces the chain In and allows the pawl to advance a notch. If someone would look into the spring and see if the new one is stronger than the old one and see when that changed and compare that to what year models tended to get a better service life out of the chain, we might have data to lead toward a better understanding of WHY it is the way it is. I suspect the spring is stiffer now. That would explain a lot.. |
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Title: Re: Cam chain tensioner revisited Post by Dave on 05/23/16 at 13:06:03 07342B2328460 wrote:
I understand what the spring is supposed to do - I just don't know that the stock spring is the proper tension for that. My guess is that the stock spring does nothing when the engine is running...the pawl does all the work when the engine is running. Once the engine cools off and contracts and sits still, likely nothing happens - then when you hit the starter button and the engine starts moving....the front side of the cam chain is tightened and the back side gets a bit of slack....and maybe the tensioner plunger moves enough to move a tooth - then by the time the engine is running the tensioner spring is doing nothing and the pawl is taking any load that is created. I think that the idea of having a spring in there is a good idea for the "warm-up" slack. |
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Title: Re: Cam chain tensioner revisited Post by norm92de on 05/23/16 at 13:34:05 I think that if the chain tension is correct when the engine is cold, i.e. has just taken up a new notch on the ratchet. The tension on the chain will be tremendous when it reaches operating temperature. Maybe if we have a real engineer amongst us they can give us some idea of the expansion of the cylinder? At the moment, I like the no pawl, metal rod in the spring idea the best. It doesn't change very much from the stock engine setup and it will eliminate the excessive tension with little risk. It could surprise us how long it lasts between re-adjustments. |
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Title: Re: Cam chain tensioner revisited Post by Dave on 05/23/16 at 13:45:36 Well......I are a "real" engineer - at least for my day Job. But to calculate how much the cylinder and head grow...you need to know a lot more about what case, cylinder, head and chain are made out of, and what temperature they are when the engine is up to temperature. I do know that the top of the cylinder head can reach 300 degrees on hot days - I have no idea what temperature the cylinder or case or chain operate at. |
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Title: Re: Cam chain tensioner revisited Post by Armen on 05/23/16 at 14:02:52 Oh boy.... I looked up the thermal expansion tables for aluminum. If I have my decimal places correct, it seems there should be about .020" of expansion of the aluminum involved with 170F increase in engine temp. Since the chain doubles over, that means .040" difference in chain length. That's using 10 to the -6 power times 13.5" expansion per degree F times 170 F and 8" of aluminum (guessing at that number, as the bike is not next to me). Anyone more awake than me care to redo the numbers? -Armen |
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Title: Re: Cam chain tensioner revisited Post by verslagen1 on 05/23/16 at 14:11:24 The cylinder has an iron core. So you're only looking at the head and case for thermal growth. The case and chain will be at the oil temperature for the most part. and the chain is longer on 1 side. |
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Title: Re: Cam chain tensioner revisited Post by gizzo on 05/23/16 at 14:51:23 20213C23777C2A2B4E0 wrote:
I have done that, plenty of times. No idea if its doable on a ninja but no problem on the thumpers I've done it to. Not done one in a long while but the chains we used came split and you rivet it togther. Never had one fail. |
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Title: Re: Cam chain tensioner revisited Post by justin_o_guy2 on 05/23/16 at 14:53:28 53405756494442404B14250 wrote:
The understanding that I have about How this problem exists doesn't help me understand what you are saying. Please don't expect me to be able to change horses midstream and suddenly grasp what you are saying. I really need you to explain that, from having seen everything I have thus far concluded. I've been explicit in what and why I see it the way I do. If you think I'm not seeing it right, and, after all, you're only an engineer and how could I be wrong, right? Anyway, if you can get it in Readers Digest terms and help me see it clearly, I would be thankful. I'd rather change my thinking and learn to be right than argue a point , be unwilling to change and be factually incorrect. If you have read what I have said, then you understand what I see. Correct me where I'm not seeing how it really is. |
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Title: Re: Cam chain tensioner revisited Post by verslagen1 on 05/23/16 at 15:00:29 4D575351506E5F4C4A4C575A595B3E0 wrote:
I have done that, plenty of times. No idea if its doable on a ninja but no problem on the thumpers I've done it to. Not done one in a long while but the chains we used came split and you rivet it togther. Never had one fail.[/quote] On our chain the pins are headed on both sides. |
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Title: Re: Cam chain tensioner revisited Post by verslagen1 on 05/23/16 at 15:06:55 584741465B5C6D5D6D55474B00320 wrote:
The understanding that I have about How this problem exists doesn't help me understand what you are saying. Please don't expect me to be able to change horses midstream and suddenly grasp what you are saying. I really need you to explain that, from having seen everything I have thus far concluded. I've been explicit in what and why I see it the way I do. If you think I'm not seeing it right, and, after all, you're only an engineer and how could I be wrong, right? Anyway, if you can get it in Readers Digest terms and help me see it clearly, I would be thankful. I'd rather change my thinking and learn to be right than argue a point , be unwilling to change and be factually incorrect. If you have read what I have said, then you understand what I see. Correct me where I'm not seeing how it really is. [/quote] You can't just simply say 12" between centers times the alpha for aluminum at 400 °F and say AHA! smoking gun and be done. After I B N ingin with ears too. |
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Title: Re: Cam chain tensioner revisited Post by norm92de on 05/23/16 at 16:04:43 If the ratchet has just taken up a tooth and the chain is taut. .020" increase between centres is enough to make the chain bow tight. Ouch! Take that! Chain and cam bearings. :'( |
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Title: Re: Cam chain tensioner revisited Post by justin_o_guy2 on 05/23/16 at 16:19:40 You can't just simply say 12" between centers times the alpha for aluminum at 400 °F and say AHA! smoking gun and be done. Okay, that is something You understand. I don't. Either the distance between centers changes or it doesn't. My understanding has been that it does. If it's Less than what I have been thinking, it's Still a change. IF that changed is Greater Than the chains length change, then the concept is still valid, though the pain induced on the chain is lessened. After I B N ingin with ears too Aaaaand, I'm so totally Not getting that.. |
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Title: Re: Cam chain tensioner revisited Post by Dave on 05/23/16 at 17:48:53 With a cast iron sleeve, and a bonded aluminum outer shell.....the expansion for the darn thing is going to be different than it would be if it was just made out of one or the other. That would have been discussed in some advance course....that I didn't take! |
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Title: Re: Cam chain tensioner revisited Post by norm92de on 05/23/16 at 18:03:31 I really like Armen's idea. It is like Batmans only with a bit of insurance. Who knows, along with Versy's mod we may see 50k out of a cam chain I think when I go into the clutch area I will take out the pawl and install a metal rod in the spring. Maybe my engine will self destruct, ;D |
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Title: Re: Cam chain tensioner revisited Post by gizzo on 05/23/16 at 18:47:09 544750514E4345474C13220 wrote:
I have done that, plenty of times. No idea if its doable on a ninja but no problem on the thumpers I've done it to. Not done one in a long while but the chains we used came split and you rivet it togther. Never had one fail.[/quote] On our chain the pins are headed on both sides.[/quote] Sure. You just need to either grind the link on one side and use your chain breaker (a decent chain breaker will break a cam chain without grinding anyway) or snip it with bolt croppers. then just use the old chain to pull the new one through. Of course you need to release any tension from the chain tensioner. The new link can be rivetted with the chain tool or by hand with a little anvil and hammer & punch. That's how I did it. I did that job loads of times back in the day. The station (ranch for you) owners used lots of XR, XT, TT 250 and 350 and would do the cam chain every 20,000km to be on the safe side. It's a lot quicker to split the chain than pull the motor down. No flywheel off, no camshaft out. Anyway that's getting off topic so back to the programme. |
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Title: Re: Cam chain tensioner revisited Post by Armen on 05/23/16 at 18:47:28 Someone said: "the chain is longer on 1 side." ? So what? Bottom line is that the distance between centers of the sprockets is increasing, and the chain is being asked to become longer by a factor of twice the cylinder expansion. Time to head to the dungeon and look for an aluminum cylinder with a cast iron liner and throw it in the oven. Most of the stuff down there is Nikasil lined. FWIW, Harley credited a lot of the base gasket leaks on the early Evo motors on fast warm-ups. The knuckle-draggers like to light up their bikes and pull away at full chat. High revs mean high oil pressure. Cold cylinders mean not as much clamping force, so the base gaskets were vulnerable to leaking. |
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Title: Re: Cam chain tensioner revisited Post by verslagen1 on 05/23/16 at 21:30:32 crank center to base of cylinder = 5" head to cam center 3.25" give or take a mile. I'm going to assume that the cylinder vs the chain = 0 net growth. thermal growth aluminum vs. steel = 12 E-6 case growth for 180°F = .007" Head growth for 360°F = .011" when hot, aluminum will grow .018" more than steel. If you remember your high school physics when calculating the load on a picture hanger wire... opposite/adjacent = tangent of the angle. when new we gotta 1" deflection in the chain let's assume the curve is in the middle... 1/(13.5/2)=.148 or 8.43° |
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Title: Re: Cam chain tensioner revisited Post by Armen on 05/24/16 at 02:52:56 Not sure why any of the angle stuff means anything. If your numbers are right, the expansion is around .018". I had guessed .020". Pretty bloody close. Moving the two points away from each other .020" means the chain is being pulled .036" (by your numbers). Assuming the pawl had taken all the slack out of the chain when it was cold, the thermal expansion means that the aluminum bits move further away from each other, stretching the chain. Think of a rear wheel. If you move it back 1/2" the chain slack will become 1" less. I don't think there is a whole lot of physics involved here. |
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Title: Re: Cam chain tensioner revisited Post by norm92de on 05/24/16 at 07:04:02 If the cam chain is like every chain I've met it will have loose spots and tight spots. That being said, if we measure the tensioner extension at the loosest point, remove the pawl and insert a steel rod that allows, shall we say, .040" more slack than that measurement. I believe the cam chain will think it is "on vacation". Sorry for the lousy metaphor. When I go into the clutch area this is the plan. Then we will see what happens, if anything. Of course the .040" is arbitrary. What is the pitch of the ratchet on the plunger? :-/ |
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Title: Re: Cam chain tensioner revisited Post by Dave on 05/24/16 at 07:59:58 2F2E332C78732524410 wrote:
I can measure that tonight and let you know. When you are making your pin.....I would most likely measure what/where the plunger is now, and then make a rod at that measurement.....or a plunger notch less. The chain will adjust to the new system in very short order - if you start with the chain too loose right way, you may need to go in and make an adjustment before long. I tried my "Hole Center Finders" in the spring last night....and the 15/64" fit inside the spring (1/4" was too big), and I don't know how easy it will be to find a steel/brass/aluminum rod in that diameter at your local hardware store. That is also 5.95mm.....so maybe a 6mm rod would fit. |
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Title: Re: Cam chain tensioner revisited Post by verslagen1 on 05/24/16 at 09:13:35 I had check my numbers cause it's kinda hard to believe. That .018" expansion equates to .060" contraction of the plunger. .009/.148=.061 and there is your smoking gun. |
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Title: Re: Cam chain tensioner revisited Post by justin_o_guy2 on 05/24/16 at 09:26:05 So, if the entire tensioner was mounted in a manner that allowed It to be pressed back when the chain pulls tight and That spring was stronger than the internal spring, then the tensioner couldn't get a new tooth so often, yet would be there, controlling the slack. That would require a Short throw,it can't be an unrestrained spring. |
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Title: Re: Cam chain tensioner revisited Post by verslagen1 on 05/24/16 at 09:36:44 Yep... what he said. :-? |
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Title: Re: Cam chain tensioner revisited Post by verslagen1 on 05/24/16 at 11:45:13 So, here's the 1st thought for an over tension device... http://www.savageriders.com/verslagen/CamChainClub/over-tension.jpg 2 plates with a spring in between. The top plate mounts the adjuster. The bottom is the anchor. spring should be 2 to 3 times as stiff as the adjuster spring. |
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Title: Re: Cam chain tensioner revisited Post by norm92de on 05/24/16 at 12:33:51 That's pretty elegant stuff. I like it. |
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Title: Re: Cam chain tensioner revisited Post by norm92de on 05/24/16 at 12:42:52 versy, Have you made one of these devices? It looks like you have. Where is the spring? |
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Title: Re: Cam chain tensioner revisited Post by Dave on 05/24/16 at 12:48:05 2E2F322D79722425400 wrote:
The red thing is the spring. |
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Title: Re: Cam chain tensioner revisited Post by norm92de on 05/24/16 at 12:54:44 I can see what you are saying but can't visualize the details. It will relieve the tremendous pressure generated by an expanding engine for sure. |
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Title: Re: Cam chain tensioner revisited Post by verslagen1 on 05/24/16 at 13:21:30 6869746B3F346263060 wrote:
I took liberties with the german version of the adjuster mod. I had tried an extension on the back end and found that the case crimped down on the adjuster housing. So I'm not sure that the german adjuster mod gets full travel. Maybe when I set this up I design it with 9mm (or so) forward so a brand new chain will fully compress the plunger. |
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Title: Re: Cam chain tensioner revisited Post by verslagen1 on 05/24/16 at 13:39:53 46595F5845427343734B59551E2C0 wrote:
That there is the stuff of inspiration, now the perspiration begins. VerSlavyJog? JogVerSlavy? [smiley=2vrolijk_08.gif] Hey wait a minute... VerJavy Yep, the mother of invention is preggy, and I'm excited. |
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Title: Re: Cam chain tensioner revisited Post by norm92de on 05/24/16 at 14:27:29 Were not talking about movement here. One eighth of an inch will be plenty. Just enough to relieve the pressure. A rubber pin to hold the adjuster? Just kidding. But you get the idea. |
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Title: Re: Cam chain tensioner revisited Post by verslagen1 on 05/24/16 at 15:26:47 we are talking more movement then a simple mod though. we need .06" we got a 9mm pin or .35" we need at least .18" in rubber. If I cut the pin down to nothing and drill out the hole till it wasn't a hole no longer, it'd work great. :-? |
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Title: Re: Cam chain tensioner revisited Post by badwolf on 05/24/16 at 16:02:08 I see this getting more and more complex, has anyone just tried putting in a weaker spring? Maybe 60% strength of stock. Leave everything else like we run now. Go to a extension when necessary. I like the K.I.S.S. method of wrenching. |
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Title: Re: Cam chain tensioner revisited Post by Dave on 05/24/16 at 16:07:29 4B495A445A584049415A280 wrote:
MMRanch has done that and has been testing it for a year or two. I just put a weaker spring in the Rescue bike with 4,000 miles on the bike. I told the lady I sold it to come back and 10,000 miles so I can check the cam chain. |
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Title: Re: Cam chain tensioner revisited Post by norm92de on 05/24/16 at 16:47:19 My guess is that the ratchet teeth are about 1mm so we get 1mm free so to speak. The real question is how much does the expansion take up of the slack in the chain. If it is indeed 1.5mm then we need to find more than that. I think as long as the chain cannot move back too much we are ok. Thus placing a solid rod inside the spring will achieve this. The pawl is the problem. When it has just taken up a new tooth the expansion of the cylinder is more than the mechanism can accommodate and the chain is placed under extreme tension. I don't think there is a problem with not having a pawl, as long as the rearward travel is limited somewhat. The stock spring provides the tension most of the time it is just when a new tooth has been acquired that we have a problem due to the pawl. |
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Title: Re: Cam chain tensioner revisited Post by Garry on 05/24/16 at 17:35:52 I wonder if removing every second tooth from the ratchet would slow down the rate of advancement of the tensioner? |
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Title: Re: Cam chain tensioner revisited Post by batman on 05/24/16 at 18:03:51 I askkid my maw why she throwd out my paw,she sayed he was a be'in a pain in her chain.She throwd him out and aint looked back agin'. |
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Title: Re: Cam chain tensioner revisited Post by norm92de on 05/24/16 at 18:17:37 I have been thinking about removing every second tooth on the ratchet. Apparently it will also be necessary to modify the pawl also to make this work. It seems that if we have more than .060" backlash the chain will not be over tensioned when starting up from cold? |
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Title: Re: Cam chain tensioner revisited Post by norm92de on 05/24/16 at 18:20:56 I hear you batman. I just haven't got the guts to remove the pawl without some kind of backlash protection. :-/ |
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Title: Re: Cam chain tensioner revisited Post by badwolf on 05/24/16 at 18:25:51 Dave, Has anyone measured the stock spring? Open length and dia. is easy. To measure the strength, put a piece of steel in the vise sticking out one side about 2 inches. Drill a 1/4' hole vertical, and place the spring on top. Measure the spring's length, then put a 3/16'' bolt down thru the spring and hole. Add weight to the bottom of the bolt till the spring compresses 1/2". Weigh the bolt and weight, multiply by 2 and that is the compression strength of the spring per inch. If we find one matching length and dia. about 60% of the strength I think it would be worth a try. |
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Title: Re: Cam chain tensioner revisited Post by Dave on 05/24/16 at 18:40:20 Removing teeth from the plunger won't work. The pawl has 2 teeth, so if you remove every other tooth from the plunger....the only thing you will accomplish is having only one toot of the pawl engaged with he remainng teeth on the plunger.......the plunger will still ratchet at the same rate. When I wanted a weaker spring....I just went to the hardware store and matched one up in diameter that was considerably weaker and a similar length. I measure the plunger extension with the stock spring, and with the new lighter spring the plunger was pushed out within a half mm of the length the stronger spring pushed.....close enough for a trial run as far as I was concerned. The spring does nothing when the engine is running as the pawl is doing the work.....the spring only moves the plunger when the engine is at rest and cool, and likely the pawl takes a new set as the starter first turns the engine over when doing a "cold start". The space between the teeth on the plunger was a bit hard for me to measure with my calipers. It appears that there was 0.910" of teeth on the plunger, and it has 23 teeth as best as I could count. That results in about 0.03956" per tooth - or about 1mm each. |
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Title: Re: Cam chain tensioner revisited Post by justin_o_guy2 on 05/24/16 at 19:47:50 If there's room, I'd make the mount hole a slot, drill through the back of the loop, in line with the tensioner arm, seat a short, stout, small diameter spring that is stronger than the tensioner spring. I could build it and see it work. Look up a few posts,, I described it , but without some detail. |
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Title: Re: Cam chain tensioner revisited Post by gizzo on 05/24/16 at 20:10:02 Here's a crazy idea for a manual cam chain adjuster: How about a ratchet device like the brake adjuster in an old drum brake system, adapted to fit where the chain tensioner lives now. The hydraulic oil sightglass could be fitted to the side cover, and removed to adjust the chain slack with a flat blade screwdriver. Obviously a bit of user skill be need to get the right tension but it might work... |
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Title: Re: Cam chain tensioner revisited Post by verslagen1 on 05/24/16 at 21:55:20 2F3036312C2B1A2A1A22303C77450 wrote:
That's doable with the right spring. Although, it'll be difficult to install. |
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Title: Re: Cam chain tensioner revisited Post by Garry on 05/24/16 at 22:21:37 So the new stronger spring would actually fulfil the roll of keeping the chain tight and preventing the plunger from ratcheting out until the chain had stretched to the point where the new springs tension was less than the plunger spring tension at which point the plunger spring would take over and allow the plunger to advance a tooth. Is that how it will work? |
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Title: Re: Cam chain tensioner revisited Post by verslagen1 on 05/24/16 at 22:37:28 no, you got it backwards. It prevents over-tension, which causes excessive wear on the chain. The stock spring keeps the tension on the chain. |
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Title: Re: Cam chain tensioner revisited Post by Serowbot on 05/25/16 at 00:06:18 A... the spring doesn't hold the chain,.. it only pushes the extender. The extender is a one way ratchet... it only tightens and never backs up... Spring pressure alone cannot do this... ...and 2... the stock spring is stronger than finger pressure, but I can easily compress it with my thumb... My thumb,.. is nowhere near strong enough to stretch a steel chain... therefore, if the slack existed to allow the spring to push adjuster, that slack existed, and won't ever go away... That makes this part of the system just fine... ...if the difference between a cold chain and a hot chain made that much difference... the stock adjuster would fall out after 15 starts... 1 notch per start,.. one stretch per ride... Even only cold days and hard rides,.. the bike wouldn't last a year... I believe we are only talking about 6 to 10 notches over the life of a chain... I don't see heat expansion... I see gradual wear... JMHO... and I'm tired.. and I admit,.. I haven't read the entire thread... That said,... thanks Versy,, for my modded adjuster. It allows me sleep at night... :) |
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Title: Re: Cam chain tensioner revisited Post by Witchdoctor on 05/25/16 at 01:12:06 382E39243C29243F4B0 wrote:
LOGIC that seems logical to me.. makes all this other crap seem irrelivant 8-) |
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Title: Re: Cam chain tensioner revisited Post by justin_o_guy2 on 05/25/16 at 05:28:39 Well, however logical you believe that to be Observed Reality has demonstrated that the tensioner is causing premature chain wear. Nobody has said the tensioner spring is damaging the chain. An engineer has seen my proposal and called it reasonable, but you guys don't Need an answer, because there is no problem. Wow,, |
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Title: Re: Cam chain tensioner revisited Post by Dave on 05/25/16 at 07:41:07 The spring in the tensioner is not overloading the chain. The part that is allowing too much tension in the chain is the pawl.....which has no ability to relax as the engine warms up. Most of the tensioners in cars are run by oil pressure, and they have a very small supply line. The tensioner can gradually adjust to the movements of the parts as things warm up - but if a sudden load is applied - the oil in the tensioner cannot be shoved out the supply line fast - so the tensioner can resist rapid movement. Our Savage does not have the ability to relax the tension on the cam chain as things warm up, and unfortunately the tensioner is establishing the chain tension when the engine is cold. |
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Title: Re: Cam chain tensioner revisited Post by norm92de on 05/25/16 at 09:20:39 Perfect analysis Dave. Thanks for measuring the ratchet spacing. I figured it must be close to 1mm. According to Versy about 1.5mm of flexibility is needed to protect the chain. How we do that is something we need to figure out. :'( |
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Title: Re: Cam chain tensioner revisited Post by norm92de on 05/25/16 at 12:57:58 The only thing I cam come up with is to curve the rear guide. Dave thinks it would be risky because of separation of the plastic. I think it would be worth a try. 1.5mm (.060")is not much. If the guide could be bent, shall we say 6 to 10mm at the centre, that would give the chain some breathing room. The biggest problem is getting the thing out of the engine. |
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Title: Re: Cam chain tensioner revisited Post by Dave on 05/25/16 at 13:51:49 22233E21757E28294C0 wrote:
I don't remember saying that - but I don't think an additional curve will help anything, and it will likely cause the guide to wear faster. We did have one member put a big curve in the guide before the Versy cam chain extension idea was born - but I don't believe he stayed around long enough to report on the survival of his curvy guide. |
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Title: Re: Cam chain tensioner revisited Post by verslagen1 on 05/25/16 at 14:10:25 I said that... and the guy that it happened to did not bend his guide. The plastic came off and clogged up his oil pump. So be warned. remember I told you so. I will snicker. [smiley=evil.gif] |
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Title: Re: Cam chain tensioner revisited Post by batman on 05/25/16 at 14:16:05 norm ,the guide will come out if you take off the top cam housing off like you do for the plug leak ,then remove the bolt the that is in the fins on the right side of the head ,undo the tensioner ,push from the bottom and it should slide out the top.only the front guide requires you to remove the head.The rear guide hangs from the bolt.I think if I where doing this I might try bending it nearer to the ends ,if you bend it in the middle it might change the profile and speed wear in a place you cant see.With ends you've only lost a little contact area where the chain enters and leaves the guide. |
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Title: Re: Cam chain tensioner revisited Post by verslagen1 on 05/25/16 at 14:27:04 3C3F2A333F306A665E0 wrote:
You'll need to remove the cam to do that. But it will come out the bottom. don't remember if I took out the chain or not. Not easy either way, but getting the arm on the bottom thru the top will be near impossible. |
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Title: Re: Cam chain tensioner revisited Post by batman on 05/25/16 at 14:47:39 verslagen sorry never been there I 'm betting your right. |
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Title: Re: Cam chain tensioner revisited Post by norm92de on 05/25/16 at 14:55:23 Versy, You rat, I hate it when you say that. ( clogged oil pump) ;D |
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Title: Re: Cam chain tensioner revisited Post by Witchdoctor on 05/25/16 at 14:58:45 43787562737F646279717C63100 wrote:
AHH yeah I see the problem now. Suzuki really doesn't give a crappity smack do they. >:( Wish they took the time to make things last a bit longer.. Its all about the $$$... |
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Title: Re: Cam chain tensioner revisited Post by justin_o_guy2 on 05/25/16 at 15:44:46 they took the time to make things last a bit longer.. Its all about the $$$... If we knew the specs on the old spring and new spring, we would have a clue. |
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Title: Re: Cam chain tensioner revisited Post by verslagen1 on 05/27/16 at 08:19:03 736C6A6D70774676467E6C602B190 wrote:
73607776696462606B34050 wrote:
I should be able to slot the mounting hole of the housing and cross drill the slot for the relief spring. I found a spring that should work and there's plenty of room for it. |
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Title: Re: Cam chain tensioner revisited Post by justin_o_guy2 on 05/27/16 at 08:45:26 I was thinking make the mount hole more sloted and, as you said, cross drill, set a small diameter, Mean little spring in the hole, slide it on the mount and have enought of a slot and enough spring to allow the tensioner to be pressed away from the chain enough to absorb the chains pressure. I think this , along with the Versy mod will change the cam chain issue. You Might sell it to Suzuki.. |
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Title: Re: Cam chain tensioner revisited Post by justin_o_guy2 on 05/27/16 at 08:51:34 d Ø .384, wire Ø .040, 2.80 length new Ø .330, wire Ø .038, 2.66 length In no Engine Ear, but the specs would make me think the new spring wouldn't be pushing as hard. And yet, chain life is generally less, so, all the variables and quality control are on the table, but QC, I'd say, leads the pack. I wish we could get reports on the special order chains... |
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Title: Re: Cam chain tensioner revisited Post by verslagen1 on 05/27/16 at 09:25:17 67787E7964635262526A78743F0D0 wrote:
Aha, you get it now. ;D The new spring is a little stiffer, not much. Hard part is installation. pushing back the spring enough to slide it on the pin maybe an issue for some. I'm thinking a bullet shaped dowel that is pushed in 1st to hold back the spring, then shove it out to mount it. |
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Title: Re: Cam chain tensioner revisited Post by norm92de on 05/27/16 at 09:42:01 Versy, Do you think you can get .060" of movement in your design? It would be great if that were possible. It should relieve the tension on the chain quite a bit. The only time it will come into play is when the pawl has just taken up a tooth. I'm surprised that Suzuki didn't come up with something similar. They could have designed a different housing altogether. |
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Title: Re: Cam chain tensioner revisited Post by Dave on 05/27/16 at 09:56:04 I think this new concept has some real potential! :) The slotted mount on the backside should provide the needed movement......now a system to provide a spring in that location is needed. Counterboring may be the easiest way, and a dowel in the hole that gets pushed out as the tensioner is pushed over the pin could work, and the user would need to keep that dowel if they ever needed to remove the tensioner and not have things fall apart. I was trying to think of a way to install a small flat "piston" in the plunger cavity - the piston could have a pin that poked out the backside of the plunger cavity to apply the force to the pin in the new slot. The problem with this scenario is I can't figure out how to make the spring apply more pressure out the backside....rather than to the plunger. It might also be possible to adapt some king of angular spring on the back of the tensioner. |
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Title: Re: Cam chain tensioner revisited Post by verslagen1 on 05/27/16 at 10:08:03 3435283763683E3F5A0 wrote:
No problem, there's about 3/8" of metal between the mounting hole and the spring cavity. Enough for a pocket and a slot, that'll compress the spring about an eighth normally and up to 3/16". |
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Title: Re: Cam chain tensioner revisited Post by justin_o_guy2 on 05/27/16 at 14:27:04 While it's true that I'm not a degreed engineer, I did design a tool to capture the broken casing downhole when two engineers failed. I've built things and solved problems for decades. If you read the post above the one that you agreed with you'll see effectively the same point made. I became The copier repairman for a small business after the other guy quit. I had seen a few repaired, been generally busy on calculators and cash register s. I couldn't even run some of the copiers. I would have someone show me what buttons to push, watch it fail, then repair it. I envisioned the necessary mods to solve this problem. So, let's try to not be looking down the nose at me. Tapering off the end of the mount pin, using a thin, stiff piece of metal, like a shoe horn, press it on. |
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Title: Re: Cam chain tensioner revisited Post by verslagen1 on 05/27/16 at 14:32:38 You're upset... :-? Did I put the wrong smiley? |
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Title: Re: Cam chain tensioner revisited Post by norm92de on 05/29/16 at 14:07:45 How much does the cylinder expand vertically when hot compared to cold? Today I tried to find out. Last night I measured the height of the cylinder when cold. I rode the bike about 100 miles so it was certainly warmed up. When I got home I measured again expecting that expansion would make the cylinder taller. No sh## Sherlock! I was surprised at the increase! My cylinder grew .5mm!! I measured from the cylinder base gasket area to the bottom of the head cap. I would think that the change in the distance between the crank center and the camshaft center would be more than this. I haven't attempted to do Versy's calculation concerning the effect on the cam chain but it seems that the cam chain would be bow tight if the tensioner had just taken up a new tooth on the ratchet when cold. :'( My measuring method was not really the best ( a caliper) but I'm certain that my numbers represent something close to reality. Versy thinks that 1.5mm is in the ballpark and I think he is being conservative. I know his doesn't solve anything but at least It seems to show how much unwanted tension is on the chain at certain times. |
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Title: Re: Cam chain tensioner revisited Post by norm92de on 05/30/16 at 14:24:04 I checked the cam chain tensioner on my Triumph Bonneville. It is very similar to the Suzuki in principle. However it has one vital difference. The nose of the ratchet plunger has a secondary more powerful spring fitted which gives it a built in cushion. If we can provide something similar on the Zuki it would probably solve the issue we are having. :) By the way, I hope the Triumph system works since I have not touched it in 16K miles. |
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Title: Re: Cam chain tensioner revisited Post by verslagen1 on 05/30/16 at 14:29:01 soooo, vasimatteryou can't snap a pic? |
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Title: Re: Cam chain tensioner revisited Post by norm92de on 05/30/16 at 14:33:11 Versy, If I could figure it out I would. :'( |
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Title: Re: Cam chain tensioner revisited Post by verslagen1 on 05/30/16 at 14:44:45 snap a pic upload it on yer computer then upload it when you post. if you can, rescale to 800x600 or 640x480. |
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Title: Re: Cam chain tensioner revisited Post by norm92de on 05/30/16 at 14:55:55 You are determined to make me work aren't you :) |
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Title: Re: Cam chain tensioner revisited Post by verslagen1 on 05/30/16 at 15:18:57 don't bother, went to flea bay and found a few. |
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Title: Re: Cam chain tensioner revisited Post by norm92de on 05/30/16 at 16:24:24 Versy, What about a 'condom' over the present plunger with a spring inside. The only problem I can see is to prevent rotation and possibly separation. Sort of like a double verslagen mod. Do you think it is worth working on? |
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Title: Re: Cam chain tensioner revisited Post by norm92de on 05/30/16 at 16:37:34 Versy, Another thought. What about a hard rubber washer inside the 'condom' Would it have enough accommodation.? How much do we need? :-/ |
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Title: Re: Cam chain tensioner revisited Post by Dave on 05/30/16 at 17:03:29 Am I the only one who has a mental problem with Winnie the Pooh working on a mechanical issue? (Maybe Normde92 needs to change his Avatar photo if he wants us to take him seriously.). Oh Bother! :-? |
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Title: Re: Cam chain tensioner revisited Post by justin_o_guy2 on 05/30/16 at 17:06:21 The pawl catches the tube. That effectively make s the tensioner a set length. The only way to allow the chain to be tightened and Not be damaged is to allow the tensioner to back away. The only easy way to accomplish that is to slot the mount and spring load it. |
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Title: Re: Cam chain tensioner revisited Post by verslagen1 on 05/30/16 at 17:54:55 4F74796E7F73686E757D706F1C0 wrote:
I think he's got his head in the honey pot. |
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Title: Re: Cam chain tensioner revisited Post by norm92de on 05/30/16 at 18:33:10 I guess growing up in England A.A. Milne and all that stuff was such a part of my life that I don't see it from your point of view. Are you trying to say that Whinny wasn't very macho? I think he was a very fierce bear. He just played his cards close to his chest. ;) |
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Title: Re: Cam chain tensioner revisited Post by batman on 05/30/16 at 18:43:36 Well while I was riding down the highway about 70mph,I was wondering if you guys were still kicking this football up and down the field. I looked down and found I'd put another 500 mi on my bike.THE GUINEA PIG LIVES!!!25500mi. still crankin'.(6500 without the pawl spring) |
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Title: Re: Cam chain tensioner revisited Post by Garry on 05/30/16 at 19:16:19 So Batman - you have disabled the pawl by removing the little spring that controls it and the plunger spring now both tensions the chain and provides shock absorbsion for the chain? |
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Title: Re: Cam chain tensioner revisited Post by DesertRat on 05/30/16 at 19:32:30 quick scan of triumph forums and a google image search: one style Triumph cam chain tensioner - http://www.bonnevilleamerica.com/dinqua/Triumph/Images/BigBore/Cam%20chain%20tensioner%20remove.jpg http://www.triumphrat.net/memberalbums/data/1289/medium/20100214_8457_1024x683.jpg or this - http://https://www.totalparts.nl/picture/boonstra/000000146073-1.jpg and the 1st thing folks do is pull that POS out and replace it with something like this - http://www.yanashiki.com/v/vspfiles/photos/YST900-2.jpg or this - http://www.brocksperformance.com/images/S13-CCT_Zoom.jpg |
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Title: Re: Cam chain tensioner revisited Post by norm92de on 05/30/16 at 19:49:03 I'm not trying to defend Triumph but my tensioner is not one of those pictured. All I can say is, mine has been trouble free for 16k miles, which I agree is not a great number of miles. Time will tell I suppose. |
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Title: Re: Cam chain tensioner revisited Post by Garry on 05/31/16 at 02:10:53 Another idea. Not sure if there is room in there? An outrigger made of thin steel which pivots on the tensioner mounting pin at the back of the tensioner and which carries a compression spring between itself and the back end of the tensioner as per the rough attached drawing. The mounting hole in the tensioner is slotted. The length of the slot could be calibrated to allow an exact amount of travel and it might be easier to try different strength and size springs? Could perhaps be better to flip the outrigger over so it is on the outside of the tensioner as this would mean that the circlip on the mounting stud is not having to deal with a slot. |
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Title: Re: Cam chain tensioner revisited Post by Dave on 05/31/16 at 03:25:33 6D6C716E3A316766030 wrote:
I don't remember him as being a good problem solver. |
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Title: Re: Cam chain tensioner revisited Post by justin_o_guy2 on 05/31/16 at 08:17:18 I seem to remember some misadventure with a honey jar. If you get outwitted by a glass jar,,,, |
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Title: Re: Cam chain tensioner revisited Post by verslagen1 on 05/31/16 at 08:53:33 Not a bad idea, garry, but orientation would be an issue. The rounded end of the housing will allow it to turn. |
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Title: Re: Cam chain tensioner revisited Post by norm92de on 05/31/16 at 12:59:31 Here we are beating our heads against the wall. While Batman is laughing at our antics. Personally I'm rooting for him. Under those circumstances the cam chain will be under constant tension. I just feel that the whole world can't be wrong so I don't have the internal fortitude to emulate him. The spring does indeed provide the tension. The pawl ONLY prevents the plunger from moving back. It is as Dave said EVERY engine uses more or less the same system. We'll see who laughs last. I want it to be Batman. When I get around to it I will remove the pawl but Will put a solid rod inside the spring as some kind of insurance. |
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Title: Re: Cam chain tensioner revisited Post by batman on 05/31/16 at 13:02:29 that "s correct Garry , I did it at 19000mi when I extended my tensioner, 2yrs ago 6500mi so far no problems. that's how all this talk about the tensioner got started (I created a monster!)If thy eye offends thee pluck it out! The pawl spring offended me so I plucked it out!!It's the K.I.S.S. system(keep it simple stupid). |
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Title: Re: Cam chain tensioner revisited Post by Armen on 05/31/16 at 13:33:46 Norm92DE, Kinda what I proposed about a million entries ago when I started this thread... -Armen |
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Title: Re: Cam chain tensioner revisited Post by norm92de on 05/31/16 at 13:45:02 Armen, I can't really see that it is a great risk. Nobody has calculated the tension on the chain when the cylinder has expanded to what I believe is about .025" but it must be considerable. The chain has nowhere to go, poor thing. It is pretty brutal to anything connected with the cam system. If we do it, everything will be normal until the chain wears a bit anyway. Batman is paving the way for us. Yeah! |
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Title: Re: Cam chain tensioner revisited Post by Garry on 05/31/16 at 16:56:07 33203736292422202B74450 wrote:
The rounded end of the tensioner could be flatted off a bit and a hole drilled and tapped to accept a suitably sized metal dowel. The metal dowel is screwed into tensioner and goes all the way through the spring and exits through a hole in the bracket. The dowel would locate the spring and bracket and slide up and down through the hole in the bracket as the spring changes length. |
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Title: Re: Cam chain tensioner revisited Post by Garry on 06/02/16 at 05:20:36 3F3E233C68633534510 wrote:
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Title: Re: Cam chain tensioner revisited Post by Garry on 06/02/16 at 06:15:43 273423223D3036343F60510 wrote:
73607776696462606B34050 wrote:
I should be able to slot the mounting hole of the housing and cross drill the slot for the relief spring. I found a spring that should work and there's plenty of room for it.[/quote] Just wondering? The spring in the slotted tensioner housing should be much stronger than the spring in the plunger? I am thinking that the new spring should be strong enough to,prevent any movement of the tensioner unit untill temperature changes start to impose strain on the chain. If the spring was too weak it could allow the chain to oscillate and might even allow the plunger to pop out another tooth. Am I thinking in the right direction? |
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Title: Re: Cam chain tensioner revisited Post by Dave on 06/02/16 at 06:25:03 Gary: The "new additional" spring does need to be stronger than the one in the plunger - but how much stronger is something yet to be determined. It could well be that the plunger spring could also be a bit weaker than the current one - I currently have one that is about half as strong and it is working just fine (MMRanch also has a very weak spring in his plunger). The plunger spring needs to only be strong enough to set an initial tension on the chain when the engine is cold and not operating......the new "additional"spring does need to be strong enough to limit excessive "oscillation" of the chain when the engine is running. I do believe the idea of cutting a window in the side of a clutch cover is a good idea for the "prototype" period....it would be nice to see what it going on when the engine is running. It is my belief that the most erratic behavior of the chains will be at startup/shutdown, and a bit less at idle, and as speed increases the load will be less erratic - however the chain may want to create a larger arc as is moves off the bottom of the crank pulley and approaches the backside chain guide. |
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Title: Re: Cam chain tensioner revisited Post by Garry on 06/02/16 at 06:57:01 63585542535F444259515C43300 wrote:
It would be ideal to have a test bench engine with a viewing window that these tests could be carried out on. I agree with your belief that the most erratic behaviour will be at start up and shutdown. But I also think that at sustained midrange revs and above the chain will tend to bow out if the guides and adjuster allow. The trick is to balance the additional spring so that it can allow for temperature variations without interfering with the normal operation of the tensioner and the guides. Every idea that appears on this forum is a step towards an answer. The conversation must continue. This will eventually be resolved! ;) I also totally agree with your take on the plunger spring. As long as it is able to still pop the plunger out at the end of its travel it is up to doing it s job. The standard spring is well above this requirement. The pawl actually does all the hard work! |
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Title: Re: Cam chain tensioner revisited Post by Dave on 06/02/16 at 07:33:02 Gary: I believe the best "bench"engine....is one mounted in the bike. One that you can take out and ride down the highway, and get fully warmed up. It would be a lot of work to set up an engine to run when it is not mounted in a bike. I do wonder how much you will really be able to see through a window in the case......the oil spray may obscure a good view of the cam chain and tensioner when the engine is running - however when you turn the engine off the oil should flow off the window pretty quickly and give you a view of where the tensioner is against the new spring setup. |
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Title: Re: Cam chain tensioner revisited Post by norm92de on 06/02/16 at 08:54:19 One thing that does come to mind. If the mounting hole is slotted the adjuster body will have to be milled a bit to accommodate a washer to prevent the circlip from being compromised. |
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Title: Re: Cam chain tensioner revisited Post by verslagen1 on 06/02/16 at 09:03:11 forces on the clip are minimal. the adjuster will be held in by the cover if it moves to much. I've seen marks on the inside of the cover that come from the assembly. |
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Title: Re: Cam chain tensioner revisited Post by norm92de on 06/02/16 at 14:34:10 Versy, I think the slotted idea will work. The proper spring will be critical. It ought to take most of the tension off the chain. Who knows, you may put yourself out of business. ;D Visualize a cam chain life of 30k before the mod is needed. |
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Title: Re: Cam chain tensioner revisited Post by verslagen1 on 06/02/16 at 14:58:25 7B7A67782C277170150 wrote:
[smiley=2vrolijk_08.gif] But who's gonna put the spring in? since this design is in every freakin' bike, I wonder how long before this mod shows up in other models? 8-) |
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Title: Re: Cam chain tensioner revisited Post by norm92de on 06/02/16 at 15:02:52 Stand by! ;D |
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Title: Re: Cam chain tensioner revisited Post by Kris01 on 06/02/16 at 15:54:01 But wait! We don't want to put Versy out of business! ;D Does anyone have access to a CNC that could cut a cover out of plexiglass? Sounds easier than trying to adapt a window to fit the stock cover. Besides, a window won't show much where a see-through cover probably would be easier to see what's going on. Perhaps even mount a camera pointing at the CCT while riding. |
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Title: Re: Cam chain tensioner revisited Post by batman on 06/02/16 at 18:07:19 With the clutch splashing oil around I suspect you not to be able to see much of anything at all with any kind of window. |
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Title: Re: Cam chain tensioner revisited Post by gizzo on 06/03/16 at 03:17:27 Look how much oil gets thrown around in this cutaway enfield engine. It's the gearbox but I guess it could be a similar story in the crankcase. https://www.youtube.com/watch?v=2V_rP88YEP0 |
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Title: Re: Cam chain tensioner revisited Post by Dave on 06/03/16 at 03:45:43 12080C0E0F310013151308050604610 wrote:
That is a lot of oil being thrown around - but it still is possible to see what it going on. (Don't try this with dirty oil). |
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Title: Re: Cam chain tensioner revisited Post by batman on 06/03/16 at 06:47:19 before you try this take off your oil fill cap and start your motor oil comes out even at idle,and there's a built in deflecter just behind it and the oil filter houseing.It's true that the piston moving down tends to pressurize the bottom end but you would have to light it to see and that's another problem. |
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Title: Re: Cam chain tensioner revisited Post by norm92de on 06/03/16 at 09:21:40 Something that has occurred to me is, if we get the 'new' spring tension wrong, cam chain harmonics could allow the tensioner to pick up a tooth on the ratchet and we didn't get anywhere. The allowable movement provided by the new slot will also be a factor. Tricky stuff! |
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Title: Re: Cam chain tensioner revisited Post by Garry on 06/04/16 at 05:14:13 That is a very good point Norm. Chain oscillation could allow the adjuster to advance and either negate the purpose of the additional spring or even impose extra loading on the chain if the pawl pops out more than one tooth. The additional spring should be very strong to resist unwanted movement of the chain. Too strong won't hurt but too weak certainly will. Who is willing to risk a motor? Then again Batman is doing fine with just the plunger spring unchained so maybe we are trying to over think this? |
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Title: Re: Cam chain tensioner revisited Post by norm92de on 06/04/16 at 07:00:28 Batman is my hero. The kiss principle is very appealing. :D |
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Title: Re: Cam chain tensioner revisited Post by justin_o_guy2 on 06/04/16 at 07:06:14 Ive thought about it. At first, I saw it as valid, but, as long as the new spring is stiffer than the old one, this is not happening.. I don't see how it could be worse than what is going on now even if the new spring, at the mount ,was weak. The chain isn't in there being subjected to bicycle chain direction changes, the crank Always spins over dragging the cam, tension is always on the front, and, the tensioner can't Grab more than the chain will give. Shutdown wheeze, or, startup cough and sputter, the chain can't get tighter than now. Once it got through the change, back to business, the spring in the end is a decent idea. Unless it's not needed, because of what Batman is doing.Let's see how that works out. What if he starts a movement against tensioner springs? |
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Title: Re: Cam chain tensioner revisited Post by norm92de on 06/04/16 at 12:59:23 JOG I think you are right. As long as the tail end spring is quite a bit stronger it shouldn't be problem. And as you say, we will not be any worse off than now. |
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Title: Re: Cam chain tensioner revisited Post by batman on 06/05/16 at 12:31:21 LOGIC! (or how to k.i.s.s. your pawl spring goodby) First let's look at a few statements made in reply to this subject. verslagen said the main plunger spring holds the tension,I agree! let's say the teeth on the pawl are almost ready to grab the next tooth on the plunger what is holding the tension on the chain? The main spring!He also said that he figured the expansion of the motor would cause the cam plunger to recede .061inches or 1.548mm.Again I agree!...So let' proceed ,after removing the clutch cover ,measure from the body of the tensioner to the center of bolt on the rear guide.Let's assume it to be 16mm.Now we remove the tensioner and then the dreaded pawl spring.Next we place it in a vice between two blocks of wood one with a slot wide and deep enough to except the tab on the base of the body.We then s l o w l y and g e n t l y compress it until it goes hard.we need to measure how far the round base of the plunger is still sticking out,let's say 4mm. while it's here in the vice grab a hacksaw blade an using the base as a guide make a shallow mark on the plunger as a reference . Now it's time to weld on your plunger extension, then drill the hole for the guide bolt 14mm from your reference mark. 16-2=14 2mm being the amount of play you've allowed for plunger to move as the motor warms . that means the tensioner goes hard after moving 2mm and then holds stronger than the pawl ever could! Now ride the hide off your bike for 5000mi then look, the mark you put on the plunger was out 2mm to start,IF it's another 2mm(I don't think it will be that much)place flat washers or whatever in the base of the body 2mm thick replace the spring and plunger,which restores your free movement back to 2mm ,if the wear remains constant your chain life should be 45000mi(that's assuming you had 15000 on it at the time of this mod) when you again reach 16mm extension.If your wear is 1mm your on your way to 75000mi . At this point I would be more worried about the wear on your guides than the chain and be looking hard at them at each 5000mi check. |
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Title: Re: Cam chain tensioner revisited Post by verslagen1 on 06/13/16 at 09:29:16 The 1st VerJavy... http://www.savageriders.com/verslagen/CamChainClub/VerJavy.jpg The new spring was checked against the original spring. Fully compressed it does not compress the new spring. I will have to repeat with the new oem spring and my replacement spring. |
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Title: Re: Cam chain tensioner revisited Post by norm92de on 06/13/16 at 12:00:21 Very nice Versy! It should work like a charm. No more bow tight cam chains. :) |
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Title: Re: Cam chain tensioner revisited Post by justin_o_guy2 on 06/13/16 at 12:10:53 That's what I pictured.. I'm convinced that is going to give the best service life of the chain. Very nice looking, too. The VerJavy,, cool,, |
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Title: Re: Cam chain tensioner revisited Post by Garry on 06/13/16 at 17:11:55 342730312E2325272C73420 wrote:
What are the specs for your new little spring Versy? Does it bear directly on the mounting pin or do you have a slug of metal in there as well? Looks like thus could be the answer. |
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Title: Re: Cam chain tensioner revisited Post by KennyG on 06/13/16 at 17:57:47 Verslagen, When you have the VerJavy perfected please let me know as I just acquired a new OEM thingy and I will send it to you for modification. Kenny G |
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Title: Re: Cam chain tensioner revisited Post by Kris01 on 06/13/16 at 18:10:37 Hurry up with the R&D! I'll be needing one really soon! ;D |
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Title: Re: Cam chain tensioner revisited Post by Violent_Rage on 06/14/16 at 03:18:03 Are you telling me that I bought two chain tensioner, facing the pains of an oceanic shipping, and just two months later the project has been modified? ARGH! :D |
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Title: Re: Cam chain tensioner revisited Post by justin_o_guy2 on 06/14/16 at 06:26:18 Now, now, let's not go into a violent rage.. But, yes, we were batting around the options, talking about Batman and his gutsy experiment,, and the notion of a slot and spring that would be far more crushable than the chain is stretchable to protect the chain when the pawl grabs a new tooth got tabled. |
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Title: Re: Cam chain tensioner revisited Post by Violent_Rage on 06/15/16 at 06:20:43 This is not fair! :D |
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Title: Re: Cam chain tensioner revisited Post by verslagen1 on 06/15/16 at 08:22:10 4C7375767F746E45487B7D7F1A0 wrote:
Still will be awhile before I can put it into production. Until you buy 1000, springs are $1 each. new fixturing, another setup, programing, testing... |
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Title: Re: Cam chain tensioner revisited Post by justin_o_guy2 on 06/15/16 at 10:03:17 What is the price break at 1,000? Don't spose it matters,, besides, a buck isn't a stopper. The additional labor, drill bits, etc. That's where I see it costing more. Do you see any need to put a hat on the spring to protect it from wearing the coil and possibly wearing through? Maybe flat spot the mount pin? |
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Title: Re: Cam chain tensioner revisited Post by verslagen1 on 06/15/16 at 10:54:47 3B242225383F0E3E0E36242863510 wrote:
There shouldn't be any motion to wear the spring. Only 1 in/out cycle per heat cycle, minimal rotational. Besides a hat would require a smaller spring. |
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Title: Re: Cam chain tensioner revisited Post by justin_o_guy2 on 06/15/16 at 10:59:33 Roger that.. thought I'd run it by.. |
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Title: Re: Cam chain tensioner revisited Post by Violent_Rage on 06/16/16 at 00:05:22 43504746595452505B04350 wrote:
I was joking ;D |
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Title: Re: Cam chain tensioner revisited Post by mjs3790225 on 06/17/16 at 13:37:43 Oh man this is an exciting development! Glad I popped in today! |
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Title: Re: Cam chain tensioner revisited Post by justin_o_guy2 on 06/17/16 at 13:44:27 Dude's in Orlando and the New and Improved design of the tensioner is exciting. Says a lot about his love of mechanical stuff. |
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Title: Re: Cam chain tensioner revisited Post by verslagen1 on 07/01/18 at 14:24:03 Well... I'm not happy with the spring. So I went back to the drawing board... http://www.savageriders.com/verslagen/CamChainClub/verjavy%20vs%20verslavy.jpg pardon my photochop verslavy... nothing on hand. |
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Title: Re: Cam chain tensioner revisited Post by faffi on 07/05/18 at 13:43:55 The number of posts reporting issues with the cam chain tensioner obviously suggest a weakness in the original design. And I am very impressed by the improved designs shown here. I do not know the cause of the rapid wear - or perhaps it is due to build tolerances, that some engines leave the factory with the tensioner already extended near its limit - but generally speaking, poor/dirty oil and chugging do tend to make cam chains wear sooner than under ideal conditions. What I find puzzling, though, is that MOTORRAD - infamous for destroying allegedly anvil strong engines after surprisingly short distances - failed to mention the cam chain or tensioner at all after their 40,000 km / 25,000 mi long term test. The second camshaft and rockers showed pitting, and 4th gear showed pitting as well, all needing replacement. But neither cam chain or its tensioner, both items considered safe for many more days on the road. Nor did any of the readers who wrote in to share their stories mention cam chain / tensioner issues that I can recall. The magazine also made a Buyer's Guide several years later, and again there was no mention of the issue. So; is this absolutely universal, or are there engines that will do 60,000 miles on the stock cam chain and tensioner, with others failing at 1/5th that for whatever reason? And anybody placed a sighting glass in the clutch cover so they can monitor the state of the tensioner? |
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Title: Re: Cam chain tensioner revisited Post by verslagen1 on 07/05/18 at 14:28:53 sure, if you can ride it 24 hours a day it'll go 60,000 miles. we believe it to be a heat cycle thing more than anything else. This is what the external spring takes care of. Do you have links for the Motorrad review? |
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Title: Re: Cam chain tensioner revisited Post by faffi on 07/05/18 at 14:51:47 Interesting theory that could well be true -MOTORRAD usually do a lot of touring, meaning longer distances per start. I do not have a link to the long term test or Buyer's Guide, unfortunately, only the magazines. Here is a link that again lead to all the links from the magazine available online, including an abbreviated buyer's tips: https://www.motorradonline.de/suzuki-ls-650/5087/alletests |
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Title: Re: Cam chain tensioner revisited Post by verslagen1 on 09/23/18 at 21:58:52 I found a spring for my new project (I hate cutting springs) And it might be the right length for those of you that want a light spring. Found it at OSH Hilman #149 compression spring 1-15/16 lg x 11/32 OD x .032 wire dia. I would like it better if it were 1/4" longer for stock use. |
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