1980 KZ1000B - rear caliper/pads won't fit over rotor

Hi y'all, first post here. Awesome forum.

I'm piecing together my absolute favorite bike of all time--a 1980 kz1000 ltd. I got the bike from a local shop (Ron's, Tulsa) in non-running *mostly* complete condition. I built one good rear caliper from 3 incomplete ones in their salvage stock (see pics). From what I can tell it's the correct caliper for the year/model.

Problem is it won't fit over the 7mm thick rotor on the rear wheel. Pistons are fully depressed, I think--they're clean and lubed, and pressed to bottom easily by hand. Pads are EBC FA 36.

Is it possible I have the wrong caliper? Were there different calipers that looked very similar in those years?

Is it possible the rear rotor was supposed to be a different thickness? Like maybe someone swapped an A model rear wheel in? Grasping at straws I know.

Any advice appreciated.

Did you try a C clamp to be sure they're bottomed?
Steve

You picked a great model for your favourite bike. I have one as well.

Your brake looks to be correct but not all there. I've attached a photo I took of mine from 5 years ago during a rebuild. Notice the wires on top.

Front and rear discs are different thickness. I think rear is thicker, but the manual will tell you what the spec is.

SWest wrote: Did you try a C clamp to be sure they're bottomed?
Steve

I did. They wouldn't budge and were both seated at identical depths relative to the bore face in the caliper.

After that I took the pistons back out and gauged the depth of the bores, height of the pistons and pads, then figured the assembled clearances to confirm they should yield about a 6mm gap between the pads. Which is what I'm actually measuring assembled.

hardrockminer wrote: You picked a great model for your favourite bike. I have one as well.

Your brake looks to be correct but not all there. I've attached a photo I took of mine from 5 years ago during a rebuild. Notice the wires on top.

Front and rear discs are different thickness. I think rear is thicker, but the manual will tell you what the spec is.

Thanks man! An '80 1000b was my first bike. Kinda biased.

I did notice I'm missing the spring clips, which is the only difference I'm seeing by the pic and the part diagram. But it shouldn't affect the gap between the pads (assuming they're manually pressed apart), unless I really misunderstand something...? My only manual is the Clymer, which is somewhat cheesy for 1979-80. It mentions 6mm as a general minimum for all years single rotors, but doesn't specify front or rear, and barely addresses brakes at all in the 1979-80 addendum. Probably right, but uncertain enough I still thought worth investigating.

Got pics up of your '80 finished?

Thanks to both of you for the replies.

A temporary fix would be to grid down both brake pads by 0,5-0,6 mm

The Kawasaki manual has the limits for dual rotors. I just did my front wheels a month or so ago so I recall reading it in the manual. That's the Kawasaki manual.

Photo below shows my bike recently. I have it in '78 paint and with a '78 head.

Scirocco wrote: A temporary fix would be to grid down both brake pads by 0,5-0,6 mm

Indeed, that's the current plan unless I can quickly figure the root of the mismatch.

hardrockminer wrote: Photo below shows my bike recently. I have it in '78 paint and with a '78 head.

Thanks for the inspiration, hardrockminer. Hope I can get mine looking that good. Long way to go.


I did notice Bike Bandit lists different part numbers for the A vs B model rear caliper in 1980:
1980 kz1000a: 43041-1013 www.bikebandit.com/oem-parts/1980-kawasa...a/o/m150586#sch81929
1980 kz1000b: 43041-1027 www.bikebandit.com/oem-parts/1980-kawasa.../o/m150607#sch741608

But there is no drawing or pic for the A model part there, nor on Kawasaki's parts website.

Probably just grind the pads and move on.

The part number I get is 43082-1002. That comes from the Kawasaki site and from Partzilla. The number is the same for the A4 and the B4. I am now wondering if you have pads for a front brake. The rotor is thinner on dual discs so the pads would possibly be thicker?