TOPIC:

Well..., our experience is only on Z1's, so might not be able to help.

Only other suggestion we have is:
Will the small end of the piston fit into the pad opening of the carrier up to the shoulder of the piston, such that the piston and carrier could be inserted into the caliper as a loose "assembly", then inserting the piston in it's bore with the carrier in place? Other than that we got nuthin'.

We're assuming you disassembled it yourself? Perhaps a FSM would be of help.

BTW, there were no KZ900's in '77 AFAIK. '77's were KZ1000's.

EDIT: Just looked at the KZ1000 FSM. Should be the same caliper. It looks like things just go together the way you're going at it. Only other idea would be to check the bore of the caliper to make sure nothing is obstructing the ability of the piston to seat completely to the bottom of the bore. Remove the caliper's piston seal (not the outer dust cover) & make sure the piston bottoms completely in the bore.

Good luck & let us know what the solution is when you find it.

Good Ridin'
slmjim & Z1BEBE

It's been a few years since I rebuilt one of those, but have you tried sliding the bracket into the body with the boots off to one side of the body, and then rotating the bracket so the boots slide behind the piston, instead of trying to push the boots over the top of the piston?

I can be wrong but your caliper piston looks a little to long. In my opinion the piston should be on the same high as the rubber dust seal.
I rebuild a lot of calipers but your piston high looks really strange.

I got it all sorted out. Should this have been easy, yes. Did I make it more difficult than it needed to be, probably.

I had trouble getting the dust seals over the piston, no matter the angle I put it in it wasn't working. Well, I lubed up the dust seals took another look at it and as I was sliding it in, much easier this time because of the lubrication, it was able to slide right in. It did not slide in at an angle, it slid in at a right angle just as the bracket would sit on the piston. The lubrication helped immensely.

I used Astroglide