I recently aquired a 1984 Honda XR 500 dirt bike. It seems to run great but at certain speeds I feel a vibration. It sounds like a bearing maybe??? It isn't bad, but it's there. It isn't rattle or loose parts or bolts. This is my first 4 stroke... Is it just the nature of the beast to have some vibration? It doesn't effect the power or performance but I can feel it

 

Don't know for sure but isn't that bike a 2 stroke and it has no counter balance wt. in motor
so has alot of vibration.

 

a xr will be a 4 stroke and a cr is a 2 stroke

 

Oops sorry guess thats the CR500

 

had a crank bearing crack on the ex and sounds like the same thing you have. it was a odd thing.

 

How do I know it is a crank bearing for shure? How do I check for that? Should I take it apart? Any suggestions?