I have a 2002 sx viper er and when I rev it to 6000 or above I have a lot of vibration in the handle bars. I believe this was due to a bad drive shaft bearing. I took it apart and the bearing on the clutch side has a little play but not a ton. I imagine when its turning that fast any little bit would be felt. Is this bearing the one that usually goes bad or the one on the chaincase side or do they wear equally?? Should I replace them both that I have it all torn down? Also the suspension on rear wheel on the clutch side would turn freely with the trackon when sitting on flat ground. Would that be caused by the worn bearig? Any comments from past experience would be greatly appericated!! Thanks Marv
Is the vibration with rpm or speed? You say over 6k but you are looking at driveline bearings.
Ya thats a good point i guess i noticed it with the rpm not the speed what would that be in the motor bearings? Also, dont know if this would contribute to the problem, but on my cylinders from crankcase to clutch are 125 psi 125 psi and 90psi quite a difference in there.
35 psi is too large of a gap. I would retest just to comfirm your numbers. Check the primary. This would be the first place I would check for rpm related vibrations.
acnas
New member
Try a different belt first. I had the same issue and put my spare on and all was good? 
90 PSI is way too low for compression.
progold
New member
I had a chaincase bearing let go on me so i tore all down and replaced all the bearings in the chaincase and drive lines,just a heads up if you can source your bearings and seals alswhere other than your local yami dealer do so for three bearings two oil seals one bolt that went missing for chaincase and one rubber seal 125 bucks ouch!!
Ok thanks for all the informations. I have done multiple wet and dry compression tests and there is always a difference, a large one, between the second and third cylinders. I went to the yamaha dealer yesterday to get the new clutch side drive shaft bearing and she wasent cheap i cant imagine doing all of them!!
mopar1rules
Active member
just so you know that the pto cylinder head dome on a stock viper head, is larger than the mag and centers, so the compression readings will be down some from the center and mag, but its usually no more than 10-15lbs.
How many miles on that Viper. Might want to check the reeds and rings maybe.
could be alot of these things but when ur losing ur rod bearings you will get a vibration in the handlebars...I guess this was a prob more with 98 and 99 srx 700s but maybe vipers have same prob
Its got about 4200 miles on it. I put in the new drive shaft bearing and I am working on putting the suspension back in right now......what a pain any tips on putting that thing back in lol.?? I got a dumb question how come they made the head bigger on that side??
progold
New member
compress the suspension using a ratcheting tie down makes the install much easier but an extra set of hands will help also.
Ok thanks for the tip i have done it that way before. I got it back in real easy actually I just loosened the bolts on the end of the action bars I think they are called and had my brother position the sledeed and the bolts went right in!!