My sled is eating rollers, and I can't figure out why. Last year, I noticed the bushings in the rollers were worn out, so i went ahead and replaced them. I rode about 400-500 miles, and they were shot again, so this time, I got the clutches aligned & pretty much rebuilt the clutch, replaced ALL bushings, new weights, rollers, and even the spring, put it all back together and again they wore out within less than a thousand miles. Then, Im thinking something is wrong with the clutch, so I tried a whole different clutch & again the rollers are shot already... any ideas? Im about ready to drop this thing off a cliff. This Sh*t's getting expensive.... and there's finaly snow, and my sled is already out of comission... 
Yamahasrx700
Member
What Mods do you have to the engine?
culvert
New member
what size rollers are you using?
YAMAHIZAL700
New member
I have good used ones if you need some cheap.
bluehammer
New member
Another question would be "are all the rollers the same diameter?".
no major engine mods, just a can but that wouldnt affect anything, I believe the rollers are 15mm the ones with one groove & yes, they are all the same size. 8ab weights p-w-p spring with 2 shims
drive line loose?
Sounds like you have something loose in the drive line that is causing the clutches to seriously come out of alignment and side-load the primary. Chech your crank end play, motor mounts and the bearings holding your secodary/jack-shaft in place.
Do you have any vibration through the handlebars or seat that started about the same time as the roller issue?
Mills
Sounds like you have something loose in the drive line that is causing the clutches to seriously come out of alignment and side-load the primary. Chech your crank end play, motor mounts and the bearings holding your secodary/jack-shaft in place.
Do you have any vibration through the handlebars or seat that started about the same time as the roller issue?
Mills
no vibrations... what do you mean by crank end play, how do i check it?
Yamahasrx700
Member
Did the Can raise your operating rpm?
not realy, but my clutching has a slight overrev, how would rpm affect the rollers?
culvert
New member
My 600MtnMx (twin) would only get 1000kms to a set of rollers. Those twins where hard on primary parts my dealer told me. Did you shim or replace the black pucks that are on the spider? They wear and cause alot of issues.
didnt shim them, but they werent too bad, the clutch that is on it now had low miles on it...
bluehammer
New member
Cracked spider?
yamaholic22
Active member
It is a harmonics issue with the yamaha twins, they are undoubtedly harder on clutch components. As mills said, things such as excess crank runout, running poor quality fuel, and overrevving can all amplify the harmonics and cause extremely rapid part failures. Check the crank runout with a dial indicator and make sure it is within spec for that engine. Run premium fuel and see if that makes a difference, and for SURE add weight to those 8AB's to make it stop overrevving. For all you know that overrev is causing the engine to operate right at one of its natural frequenices, which is causing hell for the clutch components.
what exaclty is the crack run out, how do i check it, you say with a dial indicator, but what is it that im checking for, like the lobing on the end of the crank where the clutch sits or basicly is it is bent or??? and if it isnt within spec. is there anything i can do about it?
Srxspec
Your #1 performance shop!
Buy a new clutch! You simply can not rebuild the clutches on Yamaha twins. We found this out many years ago! We would replace weights and rollers and the bushings accordingly when they were wore out and 400-500 miles later the weights and rollers would be shot again! Once the clutch on a twin cylinder wears out those components it's time to just throw the clutch away and pickup a cheap used one off of a triple cylinder sled! You can try to keep replacing components on your existing sled, but it will be a never ending battle!
crank run-out
Hoffman,
To check crank "end-play' or "run-out" you need to take your primary clutch off. Second you need to find a good dial indicator capable of measuring down to 0.0005". Set the end of the dial indicator pointer on the crank stub (portion of the crank that the primary clutch covers). Zero-out the dial indicator. Third, have someone slowly turn the engine over. As the crank spins the dial indicator will show you how much the crank moves up/down due to being bent, bearings worn or the surface of the crank being damaged. I think the max crank "run-out" on your sled should be no more than 0.006". You may want to check the tech page to make sure. Also, take a look at the inside diameter of your primary clutch where it mates to the crank - is it damaged?
If you have checked everything being suggested and still don't find anything obvious then it is probably time to replace the clutch.
Mills
Hoffman,
To check crank "end-play' or "run-out" you need to take your primary clutch off. Second you need to find a good dial indicator capable of measuring down to 0.0005". Set the end of the dial indicator pointer on the crank stub (portion of the crank that the primary clutch covers). Zero-out the dial indicator. Third, have someone slowly turn the engine over. As the crank spins the dial indicator will show you how much the crank moves up/down due to being bent, bearings worn or the surface of the crank being damaged. I think the max crank "run-out" on your sled should be no more than 0.006". You may want to check the tech page to make sure. Also, take a look at the inside diameter of your primary clutch where it mates to the crank - is it damaged?
If you have checked everything being suggested and still don't find anything obvious then it is probably time to replace the clutch.
Mills