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SuzukiSavage.com
/cgi-bin/YaBB.pl General Category >> Rubber Side Down! >> DR650 Cam Evaluation /cgi-bin/YaBB.pl?num=1525327311 Message started by DragBikeMike on 05/02/18 at 23:01:50 |
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Title: DR650 Cam Evaluation Post by DragBikeMike on 05/02/18 at 23:01:50 I have finished my evaluation of the DR650 camshaft. I have learned a few things in the process. For instance, you must use the rocker arms to establish the correct timing events. The rocker ratio changes as the rocker arm swings through it's arc. The ratio increases as the cam lobe moves the valve to towards the max open position. Geometry, should have paid more attention to that class. Here is a picture of what does not work: |
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Title: Re: DR650 Cam Evaluation Post by DragBikeMike on 05/02/18 at 23:04:09 Here is a picture of another setup with a short travel indicator. The data looked a lot better, but I could tell it still wasn't right. Gotta have those rocker arms in the mix. |
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Title: Re: DR650 Cam Evaluation Post by DragBikeMike on 05/02/18 at 23:08:10 So I bit the bullet and pulled off the head cover. Now I could check the valve timing with the rocker arms included in the mix. Here is a shot of a good setup. Note that the dial indicator is now contacting the valve adjuster tip on the rocker arm. The indicator is angled to the exact angle of the rocker adjuster. It was easy to setup and the numbers were repeatable and very accurate. |
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Title: Re: DR650 Cam Evaluation Post by DragBikeMike on 05/02/18 at 23:21:09 Here are the timing numbers on the DR 650 cam. @ .040" I/O 14 degrees BTDC I/C 46 degrees ABDC Duration 240 degrees Max lift .365" TDC lift .090" E/O 52 degrees BBDC E/C 8 degrees ATDC Duration 240 degrees Max lift .364" TDC lift .068" Valve overlap 22 degrees @ .050 I/O 10 degrees BTDC I/C 42 degrees ABDC Duration 232 degrees Max lift .365" TDC lift .090" E/O 48 degrees BBDC E/C 4 degrees ATDC Duration 232 degrees Max lift .364" TDC lift .068" Valve overlap 14 degrees |
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Title: Re: DR650 Cam Evaluation Post by DragBikeMike on 05/02/18 at 23:51:37 I am confident that these timing numbers are within +/- 1 degree and +/- .001". They are more precise than the numbers I collected on the stock cam (see prior post "cams stage1 vs stage 2 vs stage 3") because I didn't have to fight with the valve springs and alternator auto rotating the engine. Comparing the DR 650 cam @ .050" lift points to the stock LS650 cam @ .050" lift points yields the following: The DR cam opens the intake valve 30 degrees earlier. This has to promote a much better cylinder fill. Intake noise and blowback at low speed will probably increase but it should be negligible. The DR cam closes the intake valve 8 degrees sooner. This should bump up effective compression ratio and may make the engine a bit more prone to detonation. This cam is less desirable for increased compression ratios and increased displacement since increasing displacement generally increases compression ratio unless you enlarge the combustion chamber volume. The DR cam opens the exhaust valve 12 degrees earlier. This has to promote better blowdown, but the exhaust noise will probably increase a bit. The DR cam closes the exhaust valve 12 degrees later. This should improve cylinder evacuation at higher speeds. The DR cam has 14 degrees of valve overlap (stock has zero). This will promote better cylinder evacuation and fill due to the inertia of the gases. The DR cam has .030" - .032" more lift. I assume this is not a problem with spring coil bind since the DR uses the same springs as the LS and several members of the forum have reported that they are running the DR cam with the stock LS valve springs. The additional lift should get the gases in & out a little quicker. |
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Title: Re: DR650 Cam Evaluation Post by DragBikeMike on 05/03/18 at 00:05:27 Observation. I noted that the stock LS650 cam has oiling holes drilled in each lobe. Pressurized oil flows through heavy chamfers in the LH cam bearing into a void on the left side of the cam. That oil then fills the hollow cam body and is forced out through these oiling holes. I'm pretty sure the intent is to force oil between the rocker pad and the cam lobe. The DR650 cam does not have these oil holes. It is most certainly hardened steel and would be difficult to drill. A #47 drill bit fits perfectly. That's a very small bit and could break quite easily. There is a reservoir directly below the cam lobes. That reservoir is supplied oil from the RH cam bearing via a heavy chamfer. The cam lobes dip into the reservoir so they have a sort of splash lube system. Obviously, the DR cam survives without pressurized oil lubricating the lobes and rocker pads. Question is, will the LS engine function OK like that. I messaged a forum member who runs the DR cam. He was aware of the absence of the oiling holes and said his runs just fine on the splash lube system. He has logged approximately 5000 km with no adverse effects on cam or rockers. 7/13/23 This is bogus. Drill the holes. They provide lubrication for the main bearings. DBM Here is a pic of the stock LS cam oil hole. |
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Title: Re: DR650 Cam Evaluation Post by DragBikeMike on 05/03/18 at 00:06:14 Here is a pic of the DR cam without oil holes. |
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Title: Re: DR650 Cam Evaluation Post by DragBikeMike on 05/03/18 at 00:16:48 The DR cam looks like a good cam for a mildly modified engine. It does not suit the engine that I ultimately intend to build, but for now, I will probably throw it in just to see how it runs. I have the cam and I'm half done with the preps so what the heck, might as well try it. I don't think it will work well in a street application with major increases in compression and displacement. The intake valve closes too early. The engine would be harder to start, prone to detonation, and possibly be sensitive to heavy traffic and hot weather. This is bogus. The cam works great with lots more compression and doesn't pose any problem whatsoever in a street application. I was dead wrong. DBM 7/12/23 The stock DR has 9.5:1 compression so I'm sure it would work good up to that point. If you have exceptional gas in your neck of the woods (I've heard that 100 octane is available in some regions), I would say no worries. I hope this data sheds a little light on the DR cam. It's affordable and certainly an improvement over the stock LS cam. If I stick the stick in my scooter, I'll let you all know how it works. |
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Title: Re: DR650 Cam Evaluation Post by DragBikeMike on 05/03/18 at 11:52:07 BTW, regarding the indicator setups that don't work. I was taking readings directly off the cam lobes, and then multiplying those values by 1.38 to get values equivalent to movement at the valve. Since the rocker ratios are a moving target (constantly changing as the cam lifts the rocker) it just won't work. Also, max lifts calculated using cam BC vs lobe height do not agree with the numbers gathered with a dial indicator. Obviously, the indicator measures what is actually going on, so if you want actual lift at the lobe, use a dial indicator. Maybe Stephen Hawkings could have figured it out but it was way past my limited grasp of mathematics. Direct readings off the valve or rocker arm are the only way to go. |
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Title: Re: DR650 Cam Evaluation Post by hotrod on 05/03/18 at 11:55:05 Good work Mike. |
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Title: Re: DR650 Cam Evaluation Post by norm92de on 05/03/18 at 14:01:31 That was an excellent report Mike. I'm sure I can speak for most of us. Many thanks. :) |
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Title: Re: DR650 Cam Evaluation Post by kojones on 05/03/18 at 15:33:51 Excellent work and great report! Thanks! |
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Title: Re: DR650 Cam Evaluation Post by batman on 05/03/18 at 22:56:54 DBM , Another job well done ! but I don't think the valve lift has as much to do with the increase in hp and torque ,as the fact that the DR cam has overlap and the stock cam doesn't, and their duration is longer. You stated that because of the increased lift the flow in and out is faster , that maybe true as the valves first open ,and the compression is higher, but the velocity may also fall off faster as the valves open farther and the passages in the Savage head are still of poor design. |
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Title: Re: DR650 Cam Evaluation Post by DragBikeMike on 05/05/18 at 12:55:58 I guess my comment about getting the gasses in & out quicker was poorly worded. I don't mean that the additional lift will increase velocity. What I am getting at is that the cam is going to ramp the valve open a bit faster, which in turn will most likely fill the cylinder & combustion chamber faster. Of course, that's purely a guess. I'm basing that guess on the intended application. The cam was designed for an enduro bike. It's intended to provide a broad power band with good low end. Whether or not the additional lift helps or hurts the LS engine will always be a mystery to us. We don't have the resources to properly test and evaluate the additional lift. Let's face it, at a certain point, opening the valve any more won't result in additional flow. The port will be the controlling factor. But leading up to that point where the port controlls the flow, the DR cam will have positioned the valve at higher lifts than the stock cam would have provided. Also, if the ports can actually benefit from the higher lift (i.e. the port becomes the controlling factor at a lift point higher than .365"), then for sure the higher lift is beneficial. I agree that the overlap and additional duration are probably the most beneficial features of the DR cam over the LS. |
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Title: Re: DR650 Cam Evaluation Post by kojones on 05/08/18 at 05:47:29 I had a first ride with the DR cam combined with a well tuned VM36 w. UFO yesterday. A complete blast to ride, lots and lots of torque. Then I noticed some oil bursting out from between my legs, the intake valve inspection cover had came loose and both bolts were just barely on their threads. Friend brought me some oil with his Triumph Scrambler and off we go. On our ride back I noticed that both bikes have quite similar performance on a straight line, but the Savage feels like it is trying to tear my arms off ;D |
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Title: Re: DR650 Cam Evaluation Post by LANCER on 05/08/18 at 06:38:20 383C393C3D3620530 wrote:
[ch128513][ch128540] Yep, that is FUN STUFF !!! |
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Title: Re: DR650 Cam Evaluation Post by DragBikeMike on 05/14/18 at 14:08:28 I finished installation of the DR650 cam. I want give you my evaluation of the performance of the cam in this application, and also share some observations. Installation is straight forward, I did not come across any hidden mine fields. However, as previously mentioned, the DR cam does not incorporate oiling holes in the lobes like the LS cam does. I procured solid carbide bits and center drills with the intent of drilling the holes in the hardened cam lobes. But those bits are mighty tiny. I kept having this nightmare about snapping one of those little suckers off in the nice new cam lobe. After inquiring with another member who I knew was running the DR cam, I decided to chance it. I now regret that decision. Not because the cam bit the dust, but because I will be uncomfortable with the oiling issue for a good long time. I tried visual inspection through the valve covers, and with the engine in the frame you really can't see much. The only way that I can see to monitor condition is by checking valve clearance periodically. That's humbug. My concerns were valid. I believe the oil holes provide lubrication for the main bearings. I should have drilled the holes. Factory tech manual confirms main bearings get oil from top end drains. DBM 7/13/23 I examined the DR setup by reviewing the illustrated parts breakdown. The DR incorporates a part called the "Head Chamber Plate". It sort of looks like it serves as the oil reservoir that is part of the LS casting, but it could possibly be some sort of cover intended to keep oil from splashing out of the reservoir. Anyone familiar with the DR? What function does the Head Chamber Plate serve (Fig 1, part 21)? I'm thinking that at sustained high speed the cam lobes will be flinging oil out of that reservoir like crazy, and the supply to fill it only comes from the right side of the cam. Maybe I'm worried about a non-problem, but I like being sure about stuff whenever possible. If I drilled the holes I would be sure. I didn't drill them and now I'm not sure. If I had snapped off a bit all I would be out is a $165 cam and some time. Let's get to the nitty gritty. The results: 1. Cranking compression did not change one bit. It was 155 psi before I took it apart, and it was 155 psi after I put it back together. BTW, I adjusted valve lash to .004" all around. 2. Startup was normal. It fired right up with no enricher. Starter had no trouble turning the engine over. 3. Idle was too low on initial startup. I simply turned in the idle speed screw and it settled right in to a nice, smooth idle. I didn't even touch the idle mixture screw. 4. The exhaust note was audibly different. Ever so slightly louder and at a lower frequency. That's seat-o-da-pants. 5. Intake noise increased a bit. Very evident when you blip the throttle. My modified airbox was making a bit more noise but still well within DBM acceptance limits. I don't want noise and every little bit adds up. I think this will be OK. 6. Vacuum decreased a bit. I haven't had a chance to do a complete road test on vacuum, but I was able to check it at idle and when I blipped the throttle. Idle vacuum dropped from 6.5" Hg to 5.5" Hg. Throttle blip vacuum was about 3 to 8" Hg, now it's 3 to 7" Hg. 7. Test ride revealed the following seat-o-da-pants performance. When I initially took off from my driveway I immediately noted soft low end performance. Like it was very evident. The all stock motor has the performance curve of a piece of farm equipment. A dead flat major low end torque that signs-off as soon as things start getting interesting. This cam did not provide that exhilarating down low pull, but also didn't sign-off early. Don't get me wrong, it still has ample low end pull, just not as much as the stocker. Get her rolling and it now actually has a point where it hits the sweet spot. The exhilaration is now a little farther up the rpm food chain. On surface streets it felt good, on the freeway it felt better. Roll it on at 50 mph and it starts to accelerate much like the stocker, but once it hits 55 mph you can feel it hit the sweet spot. Nice, smooth steady acceleration up to 80 mph. It's clearly better on the freeway. 7.1 At no point was there any sign of detonation, pinging, or overheating. The test ride included surface streets, freeway, and winding country roads (approx. 30 miles total). The engine was well mannered under all conditions. Carburation was excellent, clean and steady, no hesitation, no flat spots, no blubber, no erratic idle, zero afterfire. After a coffee break at Mickey D's, it fired right up (none of that hot-motor starter-stall stuff, but then the compression is still 8.5). 7.2 This performance was recorded with a basically stock motorcycle. The only mods were airbox & carb jetting (covered in my prior posts). The exhaust system was untouched, and with the exception of the cam, the engine was bone stock. 7.3 I felt that this post should also include some information on how the cam would run if it was uncorked on both ends, not just the intake. So I held off on the post until I could run the cam with an exhaust system that flowed a little better than stock. I modified the stock exhaust system to reduce some of the backpressure (details & pics to follow in a separate post). I was able to reduce muffler backpressure by 6" H2O. Note that I did this without increasing the volume any appreciable amount. It still pretty much sounds like the stock muffler. Just seat-o-da-pants but it feels quite good. Very nice out on the freeway. I hit it on an uphill grade and it pulled smooth & hard right up to 80 mph. Totally sweet to pass at freeway speeds. Carburetion still spot-on. This setup works good. I hope this thread proves useful to any of you considering the DR cam. I intend to add a bit more fuel (147.5 to 150.0 and more if she will take it). Will let you know how it works. Also plan to do a dyno pull once I completely finish the exhaust (currently DBM stage I, but have some ideas for a stage II & possibly stage III). I will monitor the valve clearance as much as practicable and update this thread when I have more info. If any of you are currently running the DR cam, please share your experience. Let us know how your setup works and how the cam and rockers are holding up. If you have any sort of trick to monitor cam & rockers visually it would be quite helpful. |
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Title: Re: DR650 Cam Evaluation Post by kojones on 05/14/18 at 23:17:12 Lower vacuum kind of explains why the VM36 in mine feels to be so big of an improvement over the stock vacuum operated carb. |
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Title: Re: DR650 Cam Evaluation Post by Dave on 05/15/18 at 03:46:10 I can't comment on the DR650 oil system - but I do have a photo of what the little well looks like after running a Savage engine. This engine was run while the bike was strapped upright on my work bench, then shut down and the head cap was removed. The oil in the well under the cam is completely full. I am not sure that is stays this full while the engines is running - but it is obvious that as the engine is shut down and the oil drains from the bearings and hollow cam the little well is filled up. http://i67.tinypic.com/24df1gl.jpg |
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Title: Re: DR650 Cam Evaluation Post by DragBikeMike on 05/15/18 at 11:12:47 That is a great picture of the cylinder head with cam in place. Thanks for posting it Dave. You can clearly see those small chamfers in the cam bearing that provide oil to that reservoir. The stock cam has oil pumped through the center via the left hand cam bearing chamfer. This pressurized oil then runs through the center of the cam and out through the holes in the lobes. The hole placement is such that the oil is forced between the cam lobe and rocker pad just as the clearance is being taken up by the lobe. And of course at all other positions of cam rotation the oil is spraying out of the small holes and dribbling into the reservoir. The reservoir is also being replenished by the chamfer in the right hand cam bearing. With the DR cam, all the oiling is provided by the right hand bearing chamfer. I hope its sufficient. Certainly gonna find out over time. In my last post I mentioned that there were no hidden mine fields in the cam change procedure. I forgot about the sealant application. That is a huge hidden minefield. A seasoned veteran would probably know full well to keep the sealant application to a bare minimum, but a member new to turning wrenches might take the "if a little is good more must be better" approach. I can't stress enough how critical it is to keep the sealant away from those cam bearing chamfers. Also, thanks for posting that photo of the worn out LS cam in your other thread regarding worn rocker arms. At least now we know its not a DR cam casualty. I logged some more miles on mine yesterday while collecting vacuum data and evaluating a jet change. It's still running good and no obvious increase in valve train racket. That's a good sign. So here is the vacuum data (all a bit lower than stock): Idle 5.5" Hg Throttle blip 3-7" Hg Surface street cruise 3" Hg Soft acceleration 1-2" Hg WOT ZERO Freeway cruise 2" Hg Kojones, regarding your comment "Lower vacuum kind of explains why the VM36 in mine feels to be so big of an improvement over the stock vacuum operated carb. " If I am interpreting your comment correctly, I believe you are under the impression that manifold vacuum lifts the CV carb slide. Do I have the correct understanding of your comment? Please LMK if I understand correctly. There's manifold vacuum (vacuum in the intake manifold between the carburetor and the intake valve), and there's venturi vacuum (vacuum in the carburetor venturi resulting from increased velocity). Venturi vacuum is what lifts the slide on a CV carb. If the slide operated on manifold vacuum it would be closed at WOT. The larger main jet (from 147.5 to 150) did not seem improve performance. It actually felt like it might have lost a little but it was very subtle and hard to tell. The air quality over here is really poor right now due to VOG from the erruption on the big island. That may be a factor so i will leave it as is. It certainly wont hurt anything. When the air cleans up I'll update the thread. |
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Title: Re: DR650 Cam Evaluation Post by Dave on 05/15/18 at 11:36:05 10161965676064540 wrote:
You mean they shouldn't do this? ;) http://i65.tinypic.com/2ljnptk.jpg |
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Title: Re: DR650 Cam Evaluation Post by batman on 05/15/18 at 11:39:10 The vm36 carb should produce better low end power due to the increase in intake velocity ,in a stock or built motor. DBM thought that the earlier closing of the intake valve would increase static compression, and I thought that the increased valve lift of the DR cam would decrease it, but his tests showed that there was no change ,so they may have offset each other? |
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Title: Re: DR650 Cam Evaluation Post by DragBikeMike on 05/15/18 at 11:57:05 You can't be serious Dave. That looks like someone took great care in the application of the sealing compound. Why you can barely see the squeeze-out. If the mechanic (I use the term lightly) had used the black stuff you alerted me to, it would almost be invisible. Gosh that's ugly. |
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Title: Re: DR650 Cam Evaluation Post by Dave on 05/15/18 at 12:25:55 Sorry for posting that Drag Bike Mike.....I hope you don't have nightmares! Can you imagine what the goo that squeezed inside the motor did to the oil passages and cam? |
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Title: Re: DR650 Cam Evaluation Post by Fast 650 on 05/15/18 at 12:38:31 If you have trouble imagining it, it looks just like this. PO did exactly that to this engine. The head looked like this: |
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Title: Re: DR650 Cam Evaluation Post by Fast 650 on 05/15/18 at 12:39:17 And the piston looked like this: |
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Title: Re: DR650 Cam Evaluation Post by Dave on 05/15/18 at 14:13:37 Crap......Now I am going to have nightmares! :-? |
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Title: Re: DR650 Cam Evaluation Post by Ed L. on 05/15/18 at 15:21:44 Did that to a piston in a car once. Drove it for 10k miles with a cracked head and no oil change. LOL Ugly is what Ugly does. ;) |
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Title: Re: DR650 Cam Evaluation Post by kojones on 05/17/18 at 11:37:10 0B0D027E7C7B7F4F0 wrote:
That's exactly like I have thought it before, thanks for the clarification. Makes perfect sense. |
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Title: Re: DR650 Cam Evaluation Post by DragBikeMike on 05/17/18 at 18:05:02 Sorry, I missed another mine field. Both the stock LS cam and the DR cam have a small hole drilled in the center of the cam on the sprocket side. If you hold the cam up to a lite and look through the cam, as if it were a telescope, you should see this small hole. I think that hole is a vent to allow air to escape. When the engine isn't running, air will inevitably fill the cam. To reestablish good oil flow and hydraulic pressure, that air has to escape. If air is trapped in the hollow cam it will prevent oil flow through the cam. The trapped air will degrade top end oil pressure (air is compressible, oil is not) and inhibit oil flow through the cam for cooling. Make sure this small hole is not obstructed. What was I thinkin? Vent??? Bogus with a capital "B". The hole in the center provides lube to the steady bearing, the one on the far right-hand end of the cam. DBM 7/13/23 |
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Title: Re: DR650 Cam Evaluation Post by LANCER on 05/17/18 at 18:49:26 I have picked up a number of parts bikes with head and piston in that kind of condition. It is just N A S T Y ! ! ! Yuky even. |
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Title: Re: DR650 Cam Evaluation Post by Dave on 05/18/18 at 03:41:59 1D1B14686A6D69590 wrote:
I have seen that hole, and I do believe it does have a purpose. I imagined it was there to allow oil to flow over to the top of the cam chain and provide lubrication for the chain and guides. |
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Title: Re: DR650 Cam Evaluation Post by sparktfxr on 10/03/18 at 04:28:37 Hi Fellars..am on the tail end of a motor build after some modifications to a 2014 S40 & noticed the DR cam discussion, I used the DR cam as it seemed like a reasonable option given the shipping/time & our exchange rates in Australia. When I set up a degree wheel & dial indicator to check the cam timing it was pretty much spot on as it says on the spec sheet (new cam chain) but its a tricky process & I can see how easy it would be to be slightly out. I could with some fiddling alter the timing about 9 degs eg..instead of the inlet opening at 6 BTDC it could be 15 BTDC & all the other relevant openings & closings follow suit..which may be something to experiment with at some point but I have set them as the DR specs state. What I did do however is drill the oil holes in the cam as the 95 DR cam has only one hole looking horizontally through the centre of the cam, this hole is 1.5mm where as in my LS40 cam it was 2mm, so I enlarged it accordingly & also drilled the 2mm oiling holes in each lobe...it wasn't that difficult..the cams are just cast metal..not hardened..maybe make up a couple of wooden dollies to sit the cam in..sharp bits & take care.. I didn't have any problems & the factory must have found it worthwhile. Another point of interest to me is Ive fitted a 96mm DR piston & have read in other posts in this forum of 10.5:1 9.5:1 compression ratios with the DR piston but when I cc'd the head & did the sums for the cylinder & gasket using the bore x bore x stroke x .7854 formula all I could get was 9.1:1...are the higher comp DR pistons available?... There is so much gap between the top of the edge of the piston & the base of the head (I measured approx 5.9mm with the gasket) that there is no squish effect (the piston is much closer in a DR).. I have also opened up the ports & had the valve seats angled..am going with a 38mm mikuni round slide & a slightly larger diam header pipe with a modified muffler so am interested to find out what its like! Love riding this little bike so hopefully this will give it a bit more spirit! |
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Title: Re: DR650 Cam Evaluation Post by hotrod on 10/03/18 at 04:51:52 Nice info there sparktfxr. You and DBM are providing what I need to know. The oil hole drilling , or not, was a chief concern for me. Thanks |
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Title: Re: DR650 Cam Evaluation Post by Dave on 10/03/18 at 05:13:55 6D575351506A3E0 wrote:
We do not use the stock Suzuki DR pistons - but use the Wiseco pistons made for the DR. The Wiseco pistons are not made for the LS but are close enough that they can work - the squish is better than the stock LS piston but I still don't believe it is ideal. |
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Title: Re: DR650 Cam Evaluation Post by LANCER on 10/03/18 at 06:18:40 62585C5E5F65310 wrote:
There are 94mm Wiseco pistons available with the same crown as those made for the DR by Wiseco, which yield the higher Compression you are looking for. Whether you want the stock size 94mm, or 95/96/97mm, they are all available. The 94’s are a custom made unit that Wiseco manufactures for me. |
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Title: Re: DR650 Cam Evaluation Post by DragBikeMike on 10/03/18 at 11:31:13 The plot thickens. Just when you think you got things figured out the page turns. Greetings SPARKTFXR. I'm very interested in your experience with the DR cam. Great info on the drilling. Sounds like I should be able to pull that off with the carbide bits that I originally ordered. I just didn't have the nerve. Now that I know it can be done I think I should plan on doing it to mine. I'm very curious about the timing numbers. I installed a stock DR650 cam (1995 model year). The part number should be shown on a picture earlier in this post. The cam came in a plastic bag (shown in the aforementioned photo). The bag was factory sealed. There were no timing specifications included. I have some questions: Is your DR cam a stock, genuine Suzuki, 1995 DR650 cam, or is it some sort of aftermarket cam intended for a DR650? Did it come with a spec sheet with timing data and instructions packaged with the cam, or did you get the timing specs somewhere else? At what lift points are you taking your readings (.020", ,040", .050", etc.)? When I checked the timing at .040" & .050" I got intake opening at 14 and 10 degrees BTDC, respectively. That's why I'm so curious about your cam. Regarding your comment about altering timing, I also have given that some thought. What method are you considering (Elongating holes in the sprocket, drilling new holes, etc.). Seems to me if you advanced the timing 9 degees to get your intake opening sooner, you might end up with some detonation and starting issues since the intake would then close 9 degrees sooner. My data shows the DR cam closing the intake sooner than the stock cam. Advancing 9 degrees would aggravate that. I was considering going the other direction (retarding) by about 4 degrees. I might do that if/when I increase displacement and compression. What are your thoughts. I would really appreciate any info you can provide on your timing checks (specs, procedure, etc.). Best regards, Mike |
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Title: Re: DR650 Cam Evaluation Post by Dave on 10/03/18 at 18:44:31 One of our members (was it Armen or Gary_in_NJ) found out the number of splines on the cam drive sprocket on the camshaft can be rotated in conjunction with moving the teeth on the sprocket - and you can advance or retard the cam timing incrementally. I believe it is posted in the Tech Section. |
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Title: Cam timing Post by Armen on 10/04/18 at 02:58:00 "One of our members (was it Armen or Gary_in_NJ) found out the number of splines on the cam drive sprocket on the camshaft can be rotated in conjunction with moving the teeth on the sprocket - and you can advance or retard the cam timing incrementally." Yup, that was me. You can make some small cam timing changes by moving the cam sprockets on the crank. |
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Title: Re: DR650 Cam Evaluation Post by sparktfxr on 10/04/18 at 04:47:52 Hi fellas..the piston I used is a wiseco..p/n 4597M09600 which on the box says replaces 4597P4. The cam is a genuine suzuki DR 1995 cam from Japan in the packet with the p/n printed on the white sticker which I can't find & was sealed as you say. The specs I used are from a PROCYCLE website for stock early cam @ .040 or 1mm lift. the cam sprocket has 38 teeth & the crank 19 so you can alter it with one then bring it back by rotating the crank one tooth on the cam chain..I didn't slot the sprockets or alter its relationship with the cam in any way ..its fiddly but I checked it twice & then once again after I checked the valve to piston clearances. Im not an expert but I do have a bit of motor building experience & with the combination of pistons ect I've used I would say theres very little chance of detonation & to reap the advantages of the squish the clearances need to be on the south side of 1mm which would only be achievable with some serious engineering skills to machine off the bottom of the barrel, shorten the cam chain, slot the cam & alter the fiber cam guides..or find a piston with more metal above the gudgeon, but I would be interested if I have the wrong piston & you could point me in the right direction... On saying that I WAS dissapionted at the low number but at the end of the day Im just after a bit more pep!...not a fragile vibrating race motor. |
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Title: Re: DR650 Cam Evaluation Post by DragBikeMike on 10/04/18 at 12:49:59 Well, I'm really bamboozled now. I went to the ProCycle website and the only DR650 cam they sell is for a 96 thru current. They provide a spec sheet that shows the stock 96 thru current DR cam with intake opening at 6 degrees BTDC, same as SPARKTFXR quoted. SPARKTFXR, are you sure you got your timing data correct? It seems to me your are using the wrong specs for the 95 cam. The #190 cam they use for comparison is their cam for the 96 thru current. The numbers look nice to me but unfortunately that cam won't fit our bikes. Please double check and let us know. |
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Title: Re: DR650 Cam Evaluation Post by sparktfxr on 10/04/18 at 16:11:26 The suzuki P/N for the cam I used is 12711-12D00-000..I tried to upload a picture of the receipt but not clever enough. The cams post 1995 are as you say very different but this cam sprocket & bearing surfaces are identical to my old cam except for the slightly different lobe height & position & oil holes. The sheet you have shown is the same as the one I have so now Im a little confused as well..is the cam timing the same on the 2 different cams? because in the motor the figures match..I will keep searching the net for more evidence when I get the time but at the moment its all in the motor & it all checks out so I hope it works |
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Title: Re: DR650 Cam Evaluation Post by Drifter.. on 10/05/18 at 12:18:26 DBM, have you removed the cam yet? You mentioned you were going to check for wear on the undrilled cam and followers? How much thinner head gasket can this engine use without problems? |
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Title: Re: DR650 Cam Evaluation Post by DragBikeMike on 10/05/18 at 16:28:46 Yes. Inspected it the other night. Did a reply on hotrod’s “camshaft” post. All is well. After about 750 miles cam lobes look good. Exhaust clearance was .006” and intake .004”. So far so good. Didn’t remove cam, did visual inspection through intake valve cover opening. Tricky but certainly doable. Need to use a tiny flexible light. Tough call on the head gasket. Given the generous OEM deck height (I’m hearing it’s like -.160”) shouldn’t be any problem with clearance, but the chain tensioner is a known problem and any change in head elevation is gonna aggravate that problem. Fairly easy to correct cam timing but might be tricky to take care of the extra slack in the chain. |
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Title: Re: DR650 Cam Evaluation Post by justin_o_guy2 on 10/05/18 at 16:54:44 might be tricky to take care of the extra slack in the chain. Verslavy |
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Title: Re: DR650 Cam Evaluation Post by DragBikeMike on 10/06/18 at 06:46:31 Simply taking the slack out is not exactly what I was gettin at. You lob off the underside of the head and now the cam centerline gets closer to the crank centerline. The chain will go waaaay slack. Cam timing will be retarded, and the slack side of the chain will have to move forward, toward the drive side of the chain. At some point, it’s gonna start getting too close to the drive side of the chain. If the slack side touches the drive side, Oooooooo man that would be ugly. Might be able to re-arch the rear chain guide such that more of the slack gets taken up at points closer to the cam sprocket, areas where there is more distance between the drive & slack sides of the chain. That would probably require bucking up the rear guide with some sort of strong back to make sure it doesn’t flex. I think that’s doable. It’s certainly something I’ve been considering. I really would like to tighten up that quench zone. |
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Title: Re: DR650 Cam Evaluation Post by madmikesmech on 10/06/18 at 09:01:36 Great report DBM. |
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Title: Re: DR650 Cam Evaluation Post by batman on 10/06/18 at 10:12:02 Just a thought ,but if your trying to rid yourself of extra cam chain slack ,rather than arch the rear guide ,it may be better to arch the front guide . For one thing it's fixed in place ,and it would have the advantage of advancing the cam timing, rather than retarding it, if that's your need. |
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Title: Re: DR650 Cam Evaluation Post by justin_o_guy2 on 10/06/18 at 10:23:01 The plastic is hard, cracks would be bad. Heat might help, slow and gentle you go. |
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Title: Re: DR650 Cam Evaluation Post by Dave on 10/08/18 at 04:08:14 754F4B494872260 wrote:
You may be completely accurate in your compression calculations.......the 10.5:1 often quoted is what Wiseco lists for the piston when fitted to a DR engine. When installed in the Savage both the compression ration and deck height may be less than what would be ideal - but it is better than stock! So....maybe we can start running 87 or 89 octane? |
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Title: Re: DR650 Cam Evaluation Post by Dave on 04/22/19 at 04:05:39 At the urging of DragBikeMike....I made a fixture that allows me to drill the oil holes in the DR650 cams: Drilling http://i64.tinypic.com/2ymd0d3.jpg Countersinking http://i63.tinypic.com/n3xe2a.jpg This cam is good......the stuff that looks like pits is the chips from the drilling. |
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Title: Re: DR650 Cam Evaluation Post by batman on 04/22/19 at 08:03:07 Mike said he was multiplying the cam lobe lifts by a 1.38 advantage of the rocker arms . IF the Clymer manual is to be believed, it states that total valve lift is .330 for both the intake and exhaust(stock cam), yet the stated cam lobe lift for the stock cam is .254 /.244 . That would make the rocker arm ratios 1.299 for the intake, and 1.352 for the exhaust , That and the fact that manufacturing tolerances / and pivot shaft wear , of the rocker arms can be +/- .015 , can lead to false assumptions on total valve lift. |
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Title: Re: DR650 Cam Evaluation Post by DragBikeMike on 04/22/19 at 13:08:12 That's a thing of beauty David. Very nice job indeed. I am about to pop the top off my engine to do a head swap. I will be getting a good look at the DR cam. It has well over 1000 miles on it now, possibly close to 2000, I've lost track. I will fill you in on the results. Regarding max lift on the DR650 cam, its right at .365" at the valves. That was recorded in this post, and also in a subsequent post where I measured lobe lift for timing data (.020", .040" & .050") and valve lift for plotting the cam curves on a bunch of cams. The rocker ratio trick is a moving target because the ratio changes as the rocker swings through it's arc. I much prefer taking the actual measurement to calculating what the lift might be using a rocker ratio. I learned a lot from this drill. |
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Title: Re: DR650 Cam Evaluation Post by batman on 04/23/19 at 22:27:14 DragBikeMike , I fully agree that your actual measurements are the way to go, but for example the stock intake valve lift (.254 x 1.299 = .330 ) could range (do to the +/- .015 rocker arm tolerance) from .310 to .349 , so that moving the same cam from one motor( Head) to another might see some difference in the actual total lift , strictly caused by the change in rocker arms. I would think in some cases it might pay to move the rocker arms with the cam. |
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Title: Re: DR650 Cam Evaluation Post by DragBikeMike on 04/25/19 at 13:38:28 I am in the middle of my head swap so the engine is out of the frame. I had my first really good look at the DR650 cam and the rocker arms. I am pleased to report that all is well. The bike has right at 3000 miles on it so I believe that puts the mileage on the DR650 cam at about 1700 miles. I installed it almost one year ago. Here is a shot of the rocker arms. |
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Title: Re: DR650 Cam Evaluation Post by DragBikeMike on 04/25/19 at 13:39:11 Here is a shot of one cam lobe. |
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Title: Re: DR650 Cam Evaluation Post by DragBikeMike on 04/25/19 at 13:39:51 And here is a shot of the other cam lobe. |
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Title: Re: DR650 Cam Evaluation Post by DragBikeMike on 04/25/19 at 13:47:36 As you can see, all appears well. I have pondered this oil hole issue and have decided to leave the cam as-is. Although Dave has shown that drilling the holes is perfectly doable, I want to test the cam without the holes to see how it holds up. Although there is some risk involved, I think we can all benefit from a good look at how it holds up over the long hall. So far it seems to be holding up well. There is no indication of any sort of adverse wear. I might add, I am not a big fan of break-in procedures. I know it's the prudent thing to do, but I'm an old drag racer. You can't take your drag bike out for a 1000 mile break-in procedure. You put it together with ample clearance and run the guts out of it. That's what this DR cam got. I was WOT pretty much from day-one on this cam. It held up good so I guess it can take it. Surprise! Yes, the cam & rockers hold up well, but the main bearings don't. Be careful, this is a trap. The holes seem to be there to lubricate the cam, but IMO they are there to send additional oil down the head drains to provide lube to the main bearings. I've got over 50K on the odo and the cam lobes and rockers still look great, but the left-hand main bearing, not so great. Factory service manual says main bearings get lube from the head drains. I shoulda drilled the holes. DBM 7/13/23 |
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Title: Re: DR650 Cam Evaluation Post by Dave on 04/25/19 at 17:44:26 Pretty.....nothing more exciting then the inside of an engine that is working perfectly! :) |
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Title: Re: DR650 Cam Evaluation Post by Gary_in_NJ on 04/26/19 at 08:14:21 Holymoly that is a clean top end. We usually only see them when there is a problem. |
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Title: Re: DR650 Cam Evaluation Post by batman on 04/27/19 at 18:09:59 Dave ,did you also drill (increase) the passage down the center of the DR cam? I think I remember that was also undersized compared to stock. |
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Title: Re: DR650 Cam Evaluation Post by Dave on 04/28/19 at 04:44:40 Yes....I drilled the center of the DR cam to match the hole size in the stock cam. |
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Title: Re: DR650 Cam Evaluation Post by DragBikeMike on 07/14/23 at 01:04:34 I pulled this dinosaur up so I could do a correction. Since I initially did this post, I have changed my opinion about those oil holes in the cam lobes. Although they don't seem to have any effect on cam lobe or rocker longevity, they do seem to have a big effect on the main bearings. Especially the left-hand main bearing (large roller bearing). I have fried two of those main bearings. Turns out the left-hand main bearing gets all of its lubricating oil from the cylinder head drain. Specifically, the drain off the exhaust spring pocket (front left-hand side). It dawned on me that this old post was lost in the abyss, and I didn't want anyone digging it up and thinking it was cool to leave the holes out of the lobes. Drill the holes, they're important! |
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Title: Re: DR650 Cam Evaluation Post by Ruttly on 07/14/23 at 12:31:32 Butterfly Effect Good info :o |
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Title: Re: DR650 Cam Evaluation Post by Ruttly on 07/14/23 at 12:35:52 Grease worm infestation ! |
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