Been working on a friends 03' CR250 (purchased new late last season.) The bike was smooth and powerful until it started developing a nasty engine vibration recently. We've had no luck finding the source of this problem. Tore it down, checked all crank tolerances, put in a new piston and rings. Everything looked good - crank, clutch etc. ~expected good results. Not so. Still vibrates awful. Definitely engine related. Does it in gear or out, moving or not. Any ideas on what might cause this? :bang:
New vibration 03' CR250
- Thread starter redsput
- Start date
If all mounts are tight then the engine must be emmiting more vibration than normal. This means that a moving part is out of ballance or riding on worn bearings - to make a substaintial vibration it would have to be rather large/heavy and turn at a high speed.
Check the clutch basket bearings - remove the right side cover, grasp the clutch assy. and try to make it move up and down.
Check that the ignition flywheel is on tightly and the woodruf key is in good shape
If the above check out ok, I would have to suspect the crank. Even if the bearings are in good shape, perhaps it has shifted on the main pin slightly causing it to be out of ballance (cranks are typicaly press-fitted, though some are welded, I don't know how the 03 CR is made).
Good luck
Check the clutch basket bearings - remove the right side cover, grasp the clutch assy. and try to make it move up and down.
Check that the ignition flywheel is on tightly and the woodruf key is in good shape
If the above check out ok, I would have to suspect the crank. Even if the bearings are in good shape, perhaps it has shifted on the main pin slightly causing it to be out of ballance (cranks are typicaly press-fitted, though some are welded, I don't know how the 03 CR is made).
Good luck