I am considering returning to 15t sprocket from 16t. Just to see if acceleration is a lot better.
Anyone done this?

1. this will be long post and my English is not good so keep that in mind, i hope it will be understandable to anyone



So,

Wheels should be aligned for Z900, if bike is not dmaged in accident, chain should be aligned when wheels are aligned. I did wheels alignment before first ride, it needed it, there was discrepancy. Now at 72500km (third chain and sprockets on the bike) and never had wheels/chain aligmnent issue - i just count flats on the adjusters for chain adjustments/replacements.
Markings on swingarm are not perfect, i do not use them at all, but, in my case, 1mm difference is present: left (chain) side is more to the back on markings and wheels and chain are perfectly aligned. I do take (once per Year) wheel alignment checks and it's always fine.

When wheels are aligned (and chain should be also), best practice in my opinion is to mark one flat of the chain adjuster with paint for future adjustment (its easy, just count how many turns you move each adjuster - one flat is 1/6 of a turn so its precise more than enough and you should never check alignment again - just count the turns and do it for both left and right side the same and do it slowly so you dont lose count.


Chain should be centered between front and rear sprocket, but, there is a tolerance: if chain does not touch rear sprocket sideways as you carefuly rotate rear wheel, it doesnt matter if it sits more on one side or the other. But, if its hard against one side, there is a problem and should be fixed emediatly.

From picture above, i would say that wheel shoud be adjusted: if chain tension is OK, right (brake) side should be adjusted to bring rear wheel more to the front.
But do rotate the wheel several times in different positions because rear sprocket could be slightly offset.


Once you get that inner plates on both sides of the chain are not hard against the rear sprocket (left or right), thats good enough. Only, if sprocket is bent, or not instaled correctly, that could influence the "reading": there is a tolarance for that - spin the wheel and see if rear sprocket follows "number 8". Better yet, measure it when slowly rotating the wheel: tolerance is 0.5mm.

P.S. I would take front sprocket cover off and check if front sprocket nut is loose - usualy that nut is torqued much more than needed on Kawasakies, but, wont hurt to check (and clean cover and surrounding areas from old lube)


Hope it helps

I checked, the chain is not running centrally to the rear sprocket and is against the inner side. I manually recenter it and it will slide back to the inner side as soon as I spin the wheel. I can hear a click when I manually recenter the chain. I checked the chain marks on both side and is at the same mark, I know the markings can be inaccurate due to manufacturing tolerances. Is this normal?

Yeah valid. Same lube & cleaner as usual?

Get the bike up on a rear stand and spin the back wheel.
Does the chain runs centrally on the rear sprocket?
If its hard up against ine side nd you manually recente it does it move over back to that side as soon as you spin the wheel?

Also check the chain runs smoothly, no tight spots.