just bot 1987 250 es/r 2x for simple ranch use. seems to run well but chain comes off constantly. doesn't seem that loose. what might be causes?

 

bent sprocket would do that.. can the axle be not centered on those things like on a bike? where maybe the right side is further up than the left? I dunno.

so what's an es/r?

 

es/r is simply the particular model i am assuming as that is what is written in the side of it. "250 trail boss es/r". rear sprocket seems true doesn't seem out of line if it is how would it be corrected?

 

what about the countershaft sprocket, er, the front sprocket... not sure how the trailboss is, I think it's the same as my 87 cyclone. Really, the only things I can think of are bent sprockets (or output/countershaft)or a bad chain. Maybe the chain is overly loose... or got bad links in it and it binds as it's trying to go around the sprockets.

 

hmmm..... inspected chain seems ok but i don't know what to look for does not seem to be same spot on chain or sprocket. comes off rear sprocket to left side every time

 

Most the time when you keep loosing a chain it is due to bad axle carrier bearings or swing arm bushings or both.

 

and how would i determineif these components were a problem

 

Jack it up off the ground and start shaking the rear end and look for movment

 

the bearings could be the problem, could also be worn sprockets and possibly a bad chain that is binding....are you sure it is tight enough...because a loose chain will be the most likely problem and easiest to fix....