Do I Have A Problem Or Is This Normal ?

John: I doubt there is a problem there, but it is impossible to tell from where I sit. The only thing I would do if I thought there was a problem is put the bike up on the center stand and check for any slack in the rear hub assembly. Just make sure the rear sprocket will not turn while holding the wheel firmly. Other than that, have the dealer check it out. It is on warranty. ...J.D.

 

A chain never has the immediacy of a shaft drive and we only have your description to go by. Let’s assume you are not exaggerating ‘normal’!

There are basically 4 areas to eliminate. The first is any excessive lash in the gearbox/output shaft. The second is the security of the drive sprocket. Third is wear in the chain and sprockets and fourth is the cush drive and rear hub/sprocket carrier bearings. I would say 2” fore and aft movement of a non-running bike, in gear IS normal; less if the suspension is compressed and chain slack reduced.

I think I would be insulting your expertise to advise further on how to check!

 

John STOCUM
Yes get it back to the dealer and tell don't ask.
Regards
Joe.

 

5th area: Rear wheel spindle nut is actually tightened to correct torque. A while ago I had excessive slack/jerkiness feeling, especially braking into a corner and accelerating out of it. Found that the wheel spindle nut was half the correct torque and doing it up properly fixed the problem. So presumably braking was dragging the wheel backwards on the swing arm and accelerating was pulling it back to the chain adjuster stop

 

Due to the fact that is IS on warranty, I would not dig too deep. You could be accused of CAUSING the problem. I would certainly give the dealer a chance to look it over and make it right, if need be. Old mechanic myself. So I have been on both sides of these kind of issues. ...J.D.

 

Definitely worth having the dealer check over the machine but there is a certain amount of throttle 'delicacy' required with bikes. Too much throttle, too quickly and the power fed into the final drive will cause jerkiness (that's why there are big rubber cush(ions) between the sprocket hub and the rear wheel hub. I find this much more obvious in fuel injected bikes than in carburetted bikes. I suspect this might be the difference in the immediacy with which fuel is fed into the engine meaning much stronger throttle response which, unfortunately has the side effect of sort of off/on throttle when not handled gently.

 

I totally agree. I put a lot of it down to the transition between engine braking on no throttle and applying minimal throttle. This was so jerky on my new Bonneville Speedmaster (same engine as T120) that I even tried fitting a Booster Plug (which helped a bit). But as the miles went on the severe engine braking I noticed on the new engine got significantly less, and I removed the Booster Plug long ago, as it didn't seem to have much effect any more and may have been contributing to some running problems I was having.