Rear brake rotor size

What is the diameter of the rear brake rotor on a KZ1000 B3 (KZ1000 LTD 1979)? Mine needs to be replaced. I have ordered two off of eBay and both are a larger diameter than the one on the bike. I don't know if the one on the bike is original.
Please help!

Mike

Contact www.z1enterprises.com for good information.
Also EBC makes replacement disc's.

I haven't measured but also noted that my '79 LTD rear disc is a little smaller that what was on the '77 and 78 "A" models. I have wheels from both those bikes sitting around waiting to be used.

If you get the brake caliper holder off an earlier model, it should have the correct clearance to accept the larger disc.

Another repair to think about is to have the disc rotor built up with a metal spray and then machined to the correct thickness. Almost any metal can be vaporized and then sprayed on parts.

Here's some examples:
www.flamesprayinc.com/companyinfo.htm
www.birdsperformancecoatings.com/


I'd call around the machine shops getting prices for this.

the rear on my '78 is 10 15/16" the fronts are like 11 7/16" if that helps and it's just off the top of my head

Thanks

Mike