My rear master cylinder is leaking, No rebuild kit

I am in a bad situation here, My 1980 Kz 1000 b4 rear master cylinder is leaking, I removed the master cylinder and inspected bore, it will be ok with a light hone. I called Z1 Enterprise and they could not help me. They wanted me to check with Kzr to see if this has been addressed previously, I don't see any post on this problem. I have the master cylinder with the sepperate reservoir. I was wondering if anyone here has run into this before? I did a google search and other people have had the same problem. I would appreciate any help. Thanks, Tom

See if this posting helps you.
www.kzrider.com/forum/5-chassis/490212-r...cylinder-rebuild-kit
Or this one:
www.kzrider.com/forum/5-chassis/462374-1...rear-master-cylinder

This may not be much help, but others have reported using a rebuild kit from another model that isn't included in the cross-reference.

What they did was to compare the various aftermarket kits to their stock piston assy etc. The piston may be milled a little different and the dust boot & primary cup may not be exactly the same, but they reported that the kit worked fine. Look at Fr brake mc rebuild kits as well as the Rrs --- I recall one case in which a Fr piston kit was used at the Rr.

I believe Zoro over at the kawasakimotorcycle.org site did it - ask in the vintage section there.

There's basically the same info in the following 3 topics.
KawasakiMotorcycle.org - Rear Master Cylinder

KawasakiMotorcycle.org - Rebuild Kits For Rear Master Cylinders! Bad news first!

KawasakiMotorcycle.org - 85 GPz550 Rear Master Cylinder
The reply by zoro has a good explanation. I think someone posted comparative photos somewhere over there.

Edit: not really applicable to this topic. Just adding as a cross-reference.
KZRider topic w photos. The photos below are from the topic & by dohc (not mine)
KZR topic -->> Z1R Front Master Cylinder Rebuild Kit Substitute

I had the same problem a few years ago on my 1980 LTD 1000, I called www.google.com/url?sa=t&rct=j&q=&esrc=s&...vm=bv.53217764,d.b2I & talked to Jim, He hooked me up with what I needed to rebuild the Master cylinder, & explained everything thoroughly, 1980 was the only year they made that style of rear master cylinders, so its nearly imposable to find parts for them, but I'm sure Jim will have the parts & help you out,

Good Luck ...Pete

Ok, Thank you, very good information, this helps me to go in the right direction, i bought some used M/C on ebay, he said he would warranty it for me, we'll see if that works. I am not ready to scrap this bike over a M/C. Thanks for all your help.

Pete, that KZ looks in great condition, I would like to restore mine someday.

Thanks kzb4, I've sunk a lot of money into it over the last 30 yr's which I know I'll never see, but all the complements I get every where I go, makes it worth it to me

Thank you for your help, I took my front master cylinder apart, it was leaking also and compared seals. They looked identical, so I took a chance on it and ordered the front 5/8 brake rebuild kit from z1 enterprises. Lightly honed the master cylinder and gently removed the seals from the new piston rod and installed on rear master cylinder piston rod, and reinstalled and works great!

I did check out the other websites out for future information, Redline cycle sercice had some great stuff i'd like to get someday. Thanks again for help. Tom