|
SuzukiSavage.com
/cgi-bin/YaBB.pl General Category >> Rubber Side Down! >> Fork oil change /cgi-bin/YaBB.pl?num=1497279923 Message started by piedmontbuckeye on 06/12/17 at 08:05:23 |
|
Title: Fork oil change Post by piedmontbuckeye on 06/12/17 at 08:05:23 Over the weekend, I did my fork oil change. Mine had 9,000 miles on it, and one never knows how the previous owner really kept up. I typically try to replace all liquids and lubricants when purchasing a used anything! I am glad I did. I removed one fork at a time, and drained out old oil. Wow, was it dirty - had the look of grayishness from normal wear. I rinsed each out with kerosene and did so at least three times before kero ran clean. Then I used Marvel Mystery oil to re-lube and did so 2x on each fork then completely drained out for some time. Then I added the prescribed amount of 15w BelRay fork oil - up to 2.95" from top of fork when compressed with no spring inserted. My one question is. What weight oil do most of you use? I used 15w (from previous experience on other road bikes, and that is what someone on here recommended). However the forks seem a little too stiff now. Does any of you run 10w instead? |
|
Title: Re: Fork oil change Post by Gary_in_NJ on 06/12/17 at 08:57:09 Sounds like you did it perfectly. 15w is correct. A few things to consider: - You don't know what weight was in there previously - You don't know if they were filled correctly previously - There are no standards with fork oil. 15w from one manufacturer is not the same as 15w from another. Before declaring the forks as too stiff, ride it for a while and determine if you like the total/complete motion; ride comfort, compression and rebound. You may gain more from adding/removing some oil then a full fluid change. |
|
Title: Re: Fork oil change Post by verslagen1 on 06/12/17 at 09:27:29 mmm kerosene... wish I thought of that. 15w is what I used, seems pretty soft for my 250# bulk. |
|
Title: Re: Fork oil change Post by justin_o_guy2 on 06/12/17 at 23:01:12 My 160ish pounds can bottom the forks all too easily. |
|
Title: Re: Fork oil change Post by Dave on 06/13/17 at 04:25:00 5E4147405D5A6B5B6B53414D06340 wrote:
There is no reason to keep riding that way - it is easy to fix. Add a small amount of fork oil to each tube.....keep doing that until the bottoming out issue is resolved. If you reduce the amount of air at the top of each fork leg, it stiffens the resistance as the fork gets in the lower 1/3rd of the fork travel. It is best to measure the level of the oil with each fork tube compressed and the spring removed. |
|
Title: Re: Fork oil change Post by Gary_in_NJ on 06/13/17 at 04:57:01 Adding oil solves one problem, but creates another. We need an air chamber in the forks so the moving oil has space, otherwise the forks become hydrolocked. With an air gap of 75mm, the oil height is already VERY high in Savage to overcompensate for the poor damping and the long rake. If you want to experiment with an oil height change I suggest doing it in increments of 10mm, and then once you get "in the zone" add/remove as required for fine tuning. Each 8.55ml (0.289oz) of oil added or removed equates to a 10mm change in oil height. |
|
Title: Re: Fork oil change Post by piedmontbuckeye on 06/13/17 at 05:51:17 5B606D7A6B677C7A6169647B080 wrote:
There is no reason to keep riding that way - it is easy to fix. Add a small amount of fork oil to each tube.....keep doing that until the bottoming out issue is resolved. If you reduce the amount of air at the top of each fork leg, it stiffens the resistance as the fork gets in the lower 1/3rd of the fork travel. It is best to measure the level of the oil with each fork tube compressed and the spring removed.[/quote] I would think that the way would be to go to either thicker/thinner oil to achieve the right dampening? |
|
Title: Re: Fork oil change Post by piedmontbuckeye on 06/13/17 at 05:57:08 2F3C2B2A35383E3C3768590 wrote:
"mmm kerosene... wish I thought of that." - are you mocking me or do you really mean this? For me, I have used white (clear) kerosene to wash lots of things, and it did work (for me anyway) well for these forks. I was also very careful to be sure to thoroughly drain them before I moved on to the Marvel Mystery oil part. I used to weigh more, but am now down to about 185# - so by my losing weight, the rides seem more "stiff" to me. I am sticking with the 15w because I don't want to spend more $$ on 10w and then take the time to change it. On my dirt bikes, I used a combination of 10w and 5w to achieve about 7.5w. On street bikes I have used 15w pretty regularly. |
|
Title: Re: Fork oil change Post by Dave on 06/13/17 at 06:15:57 7B626E6F6664657F697E68606E726E0B0 wrote:
The weight of the oil is chosen so that the forks can follow the bumps and irregularities in the pavement and provide a smooth ride...a ride that is not choppy if the oil is too thick or bouncy if the oil is too thin. - the weight of the fork oil should not be altered to fork travel. The stiffness of the bottom 1/3rd of the fork travel can be adjusted and limited by the amount of air space in the forks. Start by confirming your forks have the proper weight and amount of oil in them...then add a measured amount of oil in each fork if you need a bit more stiffness in the forks as the suspension approaches the bottom of the travel. As Gary said you don't want to get too little air - but a 160 lb JOG should not be bottoming the forks. Read the comments about the Oil Level in this article: http://www.strappe.com/suspension.html |
|
Title: Re: Fork oil change Post by Gary_in_NJ on 06/13/17 at 06:24:32 4E5157504D4A7B4B7B43515D16240 wrote:
Bottoming forks is a dangerous condition. You could easily lose control. It's also an indication of a potential problem within the forks themselves such as: - Broken spring - Cracked damping rod - Blown fork seals resulting in loss of oil Get this resolved before you crash-test your leathers. |
|
Title: Re: Fork oil change Post by piedmontbuckeye on 06/13/17 at 06:33:23 I have noticed that these forks do not have a lot of travel compared to others! |
|
Title: Re: Fork oil change Post by justin_o_guy2 on 06/13/17 at 08:21:19 4F45414B40494D441A1C18280 wrote:
Bottoming forks is a dangerous condition. You could easily lose control. It's also an indication of a potential problem within the forks themselves such as: - Broken spring - Cracked damping rod - Blown fork seals resulting in loss of oil Get this resolved before you crash-test your leathers.[/quote] I just accepted it as a penalty for going too fast on crappy roads. I have been hit in the butt hard enough to pop my back a few times.. The rear bottoms too.. I'm learning the roads though, and the whoopings are decreasing. The bike has eight thousand miles on it and I'm sure she didn't hit anything to damage the thing.. I really don't want to go digging in forks. It's running through turns at almost fifty that a car would be starting to squeal tires at around 45. And rock solid doing it. When the suspension gets bottomed, I'm not just sitting there. I'm taking a beating. I totally don't like it, but bad spots exist and the roads are too inviting to Not play. I'm getting better at seeing them coming. |
|
Title: Re: Fork oil change Post by Gary_in_NJ on 06/13/17 at 08:40:03 If the roads are that crappy, I bet you blew your fork seals a long time ago and you are riding on the springs. It might be worth removing the forks (one at a time), get the fork vertical, remove the spring (slowly so the oil stays in the fork), compress the slider and then measure the air gap. If it's more than 3" you've lost oil and have blown seals. A well functioning suspension sure would be welcome on crappy roads. |
|
Title: Re: Fork oil change Post by piedmontbuckeye on 06/13/17 at 13:29:48 2C262228232A2E27797F7B4B0 wrote:
************** It would seem to me that what you are suggesting (blown seals, no oil left) would result in "boing boing boing" rather than forks bottoming out (which could happen also). Riding on just springs wouldn't bottom out unless the hydraulic process also works on the compression side of the action (which some do). It sounds to me like his step should be to either get springs with more tension or put more preload on springs. |
|
Title: Re: Fork oil change Post by gizzo on 06/13/17 at 16:20:33 that's what I was thinking, too. would be better to respring the fork to suit rider weight than fudge about trying to fix the problem with oil. the stock springs would have to be a compromise Suzuki chose to have a fork that worked ok for everyone. Sometimes it's worth tuning the fork so it works brilliantly for yourself. it's not really cheap, but worth it if you like handling. or your bike bottoms out all the time. that's no fun. |
|
Title: Re: Fork oil change Post by justin_o_guy2 on 06/13/17 at 16:27:15 I'm cornering harder than ever. I'm using the snot outta the front brakes, trying to Not miss a turn. Managed every one. No oil has ever leaked. I'm aware that the seals could get turned wrong side out. Hasn't happened yet, but it will if I don't stop finding hard dips in the shadows. |
|
Title: Re: Fork oil change Post by Gary_in_NJ on 06/13/17 at 16:58:10 A 160 pound rider should be fine on OEM springs. Springs are measured in rate (Nm, in-lb), not tension. A fork without oil or low on oil provides little damping, in compression and rebound. The lack of damping will cause them to reach full travel easily (and bong). A spring rate change is very different then damping tuning. One needs to know when it is appropriate. |
|
Title: Re: Fork oil change Post by justin_o_guy2 on 06/13/17 at 17:09:21 One may Well NEED to know, but one MAY be completely without training or desire to go digging. When I blow a seal I'll go digging. My neck popped today.. And in a low spot, completely shaded, I slowed down. On exit I looked. Reported 35, with the Kawasaki front pulley. I totally missed a dip in the shade on another stretch that bit me twice... tiptoe through and it's not bad.. It's beartraps hidden in the shade,, I gotta learn the roads, and there are So Many good fun turns and straights with little esses you can see all the way through, and there is a slight uphill right bend that straightens on a ridge and then sweeps down to the left. Really a nice piece of road. Can't wait to learn it. |
|
Title: Re: Fork oil change Post by piedmontbuckeye on 06/14/17 at 11:20:31 Adding a bit more pre-load may help - especially if original springs have allowed a little "sag" in the forks. |
|
Title: Re: Fork oil change Post by justin_o_guy2 on 06/14/17 at 11:24:58 That's something I might try out. Just a spacer on top of the spring? |
|
Title: Re: Fork oil change Post by piedmontbuckeye on 06/14/17 at 11:27:46 "Springs are measured in rate (Nm, in-lb), not tension." Doesn't a higher spring rate create more tension? Hmmmmm? Splitting semantic hairs! |
|
Title: Re: Fork oil change Post by Gary_in_NJ on 06/14/17 at 11:32:25 756C6061686A6B716770666E607C60050 wrote:
Compressing something at both ends creates "compression". Pulling something at both ends creates "tension". They are very different. Springs are rated in the amout of force required to COMPRESS a known distance. Very different. I'm just trying to help you use and understand the correct terms. |
|
Title: Re: Fork oil change Post by piedmontbuckeye on 06/14/17 at 12:01:01 6F7076716C6B5A6A5A62707C37050 wrote:
What we did in the BMW world was to take a length of plastic water pipe which had the same OD as the spring and added a length. The Savage already has a spacer up there, and then a washer then the spring. The washer is to keep the spacer from wanting to be forced between the fork and spring, so be sure to re-install it. |
|
Title: Re: Fork oil change Post by verslagen1 on 06/14/17 at 12:09:45 Adding more pre-load in the springs maybe beyond your capabilities. The caps are already hard enough to get on. But if you do want more, look at the RYCA style caps that have a adjustment screw built into them. |
|
Title: Re: Fork oil change Post by justin_o_guy2 on 06/14/17 at 12:29:43 How would I actually Decide if I need to do that? |
|
Title: Re: Fork oil change Post by Gary_in_NJ on 06/14/17 at 12:35:02 3B283F3E212C2A28237C4D0 wrote:
Because of the flange on the OEM fork cap, a cap with preload adjustment can't be used on the upper OEM triple clamp. RYCA does not sell adjustable fork caps. You can add additional preload on the spring just by adding a washer or two with an OD of 1-1/4" (the ID of our forks is 33mm). I would add them one at a time because just a few mm of preload makes a difference. But before changing preload, you need to know this: adding washers does not change the rate of the spring, it only effects sag. If a spring does not have the necessary rate for the application, all of the preload in the world will not change a thing. Preloading does not make a spring stiffer. |
|
Title: Re: Fork oil change Post by justin_o_guy2 on 06/14/17 at 13:35:52 I understand it doesn't change the rate, it just starts with a higher initial number of pounds of pressure holding the suspension extended. That might be a good idea, IDK. I'm liking the trail brake Set I'm getting with such low brake pressures. |
|
Title: Re: Fork oil change Post by batman on 06/14/17 at 14:58:09 I have heard of using 1 1/4 " PVC pipe to lengthen the spacer in the fork and place more preload on the spring ,or placing washers on top of the stock spacer which would do the same but decreases the amount of room for the air above the fork oil . how do they differ in effect? |
|
Title: Re: Fork oil change Post by Ruttly on 06/14/17 at 15:15:57 I used Ryca lowering kit with Progressive springs and oil level recommended by Progressive in the instruction sheet with ATF and shortened stock spacer by 1 inch. Handles very nice , brake dive wasn't to bad with stock binder but installed Shawn's big brake now it got some dive , but still very controllable. |
|
Title: Re: Fork oil change Post by Gary_in_NJ on 06/14/17 at 15:17:45 If you don't like the idea of multiple washers and a spacer, you can dial in the preload with washers, and when you get the sag where you need it (about 10 to 15mm) you can remove the spacer and the washer, measure the stack, and replace it with a single piece of PVC at the right length. Adding washers is as easy as it sounds. Remove the fork cap (one at a time some the forks don't compress) and add a washer. Do the same on the other side. Then measure sag. |
|
Title: Re: Fork oil change Post by Ruttly on 06/14/17 at 20:07:28 Gary , Is that the norm 10-15mm or what you recommend for a stock fork or a shortened fork ? Asking a question not doubting you ! You explain things so well , can you please elaborate so this dummy can understand it. Thanks |
|
Title: Re: Fork oil change Post by Gary_in_NJ on 06/15/17 at 05:21:28 The free sag settings on the bike tell us whether we have the correct spring rate. With the correct spring rate we know that the suspension will provide adequate performance so the forks don't fully compress under load (a dangerous condition). There are two sag settings that we need be aware of; "free sag" (the weight of the bike only on the suspension) and "race sag" (the weight of the bike and rider on the suspension). Race sag is a user set value, and Free sag is a result of the set value. Ideally we want to use 30% of the suspension travel for race sag. The Savage forks have 127mm of travel, so the target race sag is 38mm (1-1/2 inch). I can't find the swingarm travel for a Savage, but my guess it is only 2 to 3 inches, so the race sag would be a little over 1/2 to less than an inch. Lets call it 3/4 inch. Race sag is adjusted through preloading the springs; washers for the forks and the collar on the shock. Take measurements from fixed points with the suspension completely extended (jacked up) to get baseline measurements. From there have someone steady the bike while you sit on it. Take measurements from the same fixed points. If you overshot the target you need additional preload. If you didn't reach the target you need less. After these measurements and adjustments have been made it's time to measure the free sag. The target for free sag is about 10mm (probably just 5 for the rear given its limited travel). If your race sag is correct but free sag is less than recommended (10mm) or if the suspension is topping out, a heavier spring rate is indicated. Just the opposite applies, if free sag is more than the target a lighter rated spring may be needed. |
|
Title: Re: Fork oil change Post by piedmontbuckeye on 06/15/17 at 16:01:52 Remember, adding spacers (via washers or tubing) will compensate for sag if original springs have weakened (which could be due to the fact of bottoming out). There is always normal sag (as explained by another post in this thread, but you want to note any non-normal sag due to spring weakening. Spring weakening can be compensated for by adding more preload, but keep in mind that if they are too weak, they will end up in bottoming out due to coil bind. For this, the best is to replace with new springs or springs with a high compression rate. Unless very low, adding or deleting fork oil under these conditions will not improve anything. |
|
Title: Re: Fork oil change Post by Gary_in_NJ on 06/15/17 at 16:28:42 504945444D4F4E544255434B455945200 wrote:
A "weaker" spring is a spring that does not meet its design specification. You can not alter the rate of a spring through preloading. Preloading does just that, it places a load on the spring. It does not alter or change the rate, i.e. the amount of force required to move the spring a fixed distance such as lb-ft (1 lb of force moves the spring 1 ft). If a spring doesn't meet it's design spec, it should be replaced, not preloaded. |
|
Title: Re: Fork oil change Post by piedmontbuckeye on 06/16/17 at 16:52:15 Contrare. First, I did not say that one can alter the spring rate by adding spacers! Adding spacer(s) has been done for years to compensate for weakened springs. The spring/rate nomenclature that you refer to is a rate. While, as per your example, 1 lb moves spring 1 foot, the second foot takes more than another pound - the rate changes proportionally, and adding pre-load takes the same length spring and pre-compresses it a bit because that second "inch" will then take more pressure to compress than the first "inch" did under original setup. Weakened springs most often are shorter than their original length. That's why mechanics use uncompressed spring length as a deciding factor in whether to replace a spring. There is usually a "tolerance" there - after it gets so short - then replacement is needed. A good example can be had on the rear springs/shocks on a motorcycle. Not the progressive type that allow changeable hydraulics of the oil, but the ones (as on our LS650's) with the changeable rotating rings at the bottom. By rotating the ring to add pre-load to the shock spring, does it, or does it not make the rear shocks harder to compress? Same rate spring, but now "pre-loaded" a bit by the ring. Makes the rear end stiffer. Right? That feature is provided as a cheap way to allow some user adjustment for rider weight, or for riding double. Only question here, is that if the forks are already bottoming out (either reaching full travel, or the springs are going to coil bind) then pre-load may not help as the springs, no matter how much compressed by pre-load, will also probably bottom out as well. |
|
Title: Re: Fork oil change Post by piedmontbuckeye on 06/16/17 at 17:01:39 1B3C3D3D2530490 wrote:
The rule is to measure the length of current spring and compare it with the original length of a new spring. Add a spacer (in addition to any existing original spacers) of the same length that the older spring is in comparison to original spring. Check specs. as with any thing that wears with use (for example: brake rotor thicknesses) it will have predictable wear (shortening) but when it falls under the tolerance permitted, it should be replaced. |
|
Title: Re: Fork oil change Post by gizzo on 06/16/17 at 17:26:15 3C252928212322382E392F272935294C0 wrote:
Wrong. It raises the bike a bit and loses you a bit of suspension travel. I'd rant on but it'd be a waste of time and Gary has described it perfectly anyway. "Adding spacer(s) has been done for years to compensate for weakened springs. " is just a cheap arse way of avoiding buying springs that do the job that's required of them. In no way will a spring with spacers provide an improvement in handling. |
|
Title: Re: Fork oil change Post by piedmontbuckeye on 06/16/17 at 17:57:11 You are wrong! Changing the ring on the back of a bike shock does not raise the bike a bit! It adds a bit of "pre-load" and thus makes the shock/spring harder to compress - to compensate for the added weight! On the front adding a spacer will raise it back up to compensate for spring sag. It has been done for years! While replacing the springs with either springs of a higher spring rate or with original new springs is an alternative. Using spacers has done the trick for years and years! It all depends upon how badly the original springs have compressed and lost their "spring." |
|
Title: Re: Fork oil change Post by gizzo on 06/16/17 at 19:48:15 Well as long as you're content and can't tell the difference, that's all that matters. More power to ya. |
|
Title: Re: Fork oil change Post by justin_o_guy2 on 06/16/17 at 23:03:35 Whoever is able to bolster his position with information about suspension and spring rates and all that wins. I'm sure not able to mount an argument against either of you. |
|
Title: Re: Fork oil change Post by Ruttly on 06/17/17 at 07:08:09 I won't bother to argue with some one who doesn't know , cause I might not be right. If you have a question about suspension and you want the correct answer don't waste your time arguing , just ask Gary. He has proven to be a wealth of information on the subject. It's all in his head and all you have to do is ask. |
|
Title: Re: Fork oil change Post by piedmontbuckeye on 06/17/17 at 07:33:36 745352524A5F260 wrote:
Agreed! I suspect that both of us are correct in some fashion or another. Perhaps I am confusing Compression RATE with Compression LOAD. I just refer back to the rear shocks and how one makes them more resistant to compression and that is the pre-load ring at the bottom. Allows for more load to compress From experience, however, we have for years done the extra tube at the top of fork springs to help against front sagging or bottoming out. Has worked. I agree however that the best solution is to purchase new springs if old have worn out and allow more sag. What bothers me in this whole scenario, is that the question started because a fairly light guy (160 Lbs?) was having the forks bottom out. That puzzles me. I am around 200 Lbs. and I have never had front forks bottom out or coil bind. Except on race bikes where I came down head first on the front wheel! Seems that there might be another problem than just fork oil quantity or fork spring. Fork springs last a long time and for one to go bad would be highly unlikely. |
|
Title: Re: Fork oil change Post by Gary_in_NJ on 06/17/17 at 07:34:20 607975747D7F7E647265737B756975100 wrote:
I'm going to be kind here and suggest that you stop trying to explain how springs work. Please review Hooks Law F=-kx, where kx=ma |
|
Title: Re: Fork oil change Post by justin_o_guy2 on 06/17/17 at 09:22:52 Yeah,I SAID it bottomed out a few times. If it Didn't, I sure would hate to be there if it ever does. I didn't Measure anything. I saw signs of fork travel, but didn't SEE if it was enough to bottom out. I guess I bottomed it. It was painfully violent, but it was also a surprise. Going in and out of bright sun and dark shadows on roads that are very minimally traveled and far from the concerns of the road and bridge guys. The parts that invite a spirited approach lead into some places that look okay on approach, but there can be hidden hazards. A couple of times I fully expected a fork oil spray. If I didn't bottom out and bottoming out is more violent than what I have seen, I Sure don't ever want to bottom it out. It handles fine, no oil leaks, a brake on Push Pull doesn't show excessive travel or any noise. |
|
Title: Re: Fork oil change Post by Ruttly on 06/17/17 at 10:43:44 I love that word "nomenclature" it sounds so technical. What is your profession Gary ? |
|
Title: Re: Fork oil change Post by piedmontbuckeye on 06/17/17 at 13:53:22 52585C565D545059070105350 wrote:
I'm going to be kind here and suggest that you stop trying to explain how springs work. Please review Hooks Law F=-kx, where kx=ma[/quote] I am familiar with what you are referring to. I learned in Physics class.. But nothing there invalidates what I said about the original issue: That is, using spacers to increase pre-load to compensate for possible sagging forks. Now, that's being kind. |
|
Title: Re: Fork oil change Post by justin_o_guy2 on 06/17/17 at 13:57:58 Of Course you're gonna be kind. You don't wanna wake up and see PiedmontBuckEye is now PiedmontBlackEye. |
|
Title: Re: Fork oil change Post by Gary_in_NJ on 06/17/17 at 20:19:15 5D7A7B7B63760F0 wrote:
Sales Engineer in the aerospace industry. |
|
Title: Re: Fork oil change Post by gizzo on 06/17/17 at 20:47:51 JoG: You probably know this but just in case, if you're interested to see how much your fork is really compressing through those bumps, put a zip tie around a fork leg down by the seal. The fork compressing will push the zip tie up the leg and show you how much travel you used. |
|
Title: Re: Fork oil change Post by justin_o_guy2 on 06/17/17 at 23:55:10 I'll do that |
|
Title: Re: Fork oil change Post by Ruttly on 06/18/17 at 20:10:40 Gary , Pardon my ignorance but what is a Sales Engineer ? I'm sure you already figured out I'm not a rocket scientist. ;D |
|
Title: Re: Fork oil change Post by Gary_in_NJ on 06/19/17 at 05:27:57 193E3F3F27324B0 wrote:
I work for a company that makes actuators for aircraft, UAV, missiles and some military ground equipment. In addition to seeking new opportunities for my company, I work with the OEM design team to help develop specifications for electro-mechanical actuators. The REAL engineers at the company look at system kinematics and design/develop the gear train and motors required to meet the specifications. |
|
SuzukiSavage.com » Powered by YaBB 2.2! YaBB © 2000-2007. All Rights Reserved. |