Best way to check drive train backlash?

[Doctor Shifty]

On my 81 GS1000G there is more lash than I think is warranted. The move from throttle off to throttle on gives a bit of a jerk through the system that I would like to get rid of. Trouble is, there are several places which can be the culprit.

What is the best way to check where the movement is?

[Dave8338]

Most likely it is in one of two places or both. The most likely culprit is in the primary output gears (closest to the engine). They are the smallest of the gears and as a result, take the most punishment on acceleration and deceleration. Second and nearly as likely...are the damper blocks in the final drive unit. With age and miles, they get weak and loose their rebound and if the seals in your final drive unit are leaking, it only worsens the problem.

I'd put the bike in first gear and with it on the center stand, rotate the rear wheel back and forth, while listening for a slight "clunk" up near the enging. If there is a great deal of movement in the wheel before it hits the resistance of the gears, up to 1/4 turn, you most likely found the problem. There will be some slack in the drive unit, even when new. If it seems tight and there is no noticeable slop in that area, you are probably looking into replacing the damper blocks in the rear of the final drive.

[SqDancerLynn1]

It could also be that the wheel adapter splines are getting ready to go south & is the FIRST thing to check

[Doctor Shifty]

Thanks for the tips. I'll have a careful listen to the thing when I get it out tomorrow.

Kim