surging and lag

[99gz250]

I bought a 99' Gz250 that sat for a couple years and want to add my discoveries to the forum.

Got it running after cleaning the carb, changing oil and filter and plugs then battery.

Riding symptoms were erratic surging when accelerating and slight lag from idle. It also was clunky when releasing the clutch from a stop or engaging first gear with clutch in.

First of all oiled the chain well and symptoms remained. Also too much difference between tight and loose after adjustment spec. Really sloppy.
Removed the continuous oring chain and it was binding in several spots. The front sprocket was slightly worn. Rear looked ok.

After changing the frt. sprocket and went to a non o-ring chain with clip, the surging went away.

The clunk remained.

I read that there is supposed to be some play in the rear sprocket and it will move a little normally. In my case this is INCORRECT. The cush drive rubber inspected was slightly frayed and looked solid but I decided to order a new one.

After installing, there WAS NO PLAY noticeable in the rear sprocket and the clunkiness and lag upon acceleration is now gone.

I now think, should have went with a 16t frt. sprocket, brain fart but maybe next time.

Have one question, on the torque link arm nut closest to the rear hub.
I feel like I stripped the nut and it just tightens and spins. So I left it and put the cotter pin in.

How tight should this be and when should it be tightened? I did it last after adjusting chain and torqueing axle bolt.

Thanks, this site is a wealth of information and I sincerely appreciate it.

[99gz250]

I figured out my torque link problem.

The bolt and nut were not stripped. The lock washer was compressed flat like a regular washer and not functioning correctly so the nut screwed too far in and resulted in a loose fit.

This loose fit, together when applying the brakes resulted in a "grab."
Just replaced the lock washer and all is well!