biggest rear tire for kz650 c1

can anyone tell me whats the widest tire you can fit on a stock kz650 c1 rim

I bought a KZ650 last year and it had a 150/90 on it. I couldn't believe it as that is the size tire i run on my 1000 with extended swingarm. I think this bike was a 1978. Roy

The rim is only a 2.15" width. A 120/90-18 does the job pretty good. Any bigger than that isn't going to benefit you at all with the narrow rim.

On the stock rim - 130/90V18. Even that may require a slight mod to the stock chainguard. I ran that size for years on my stock KZ650-C1. The 130 is hard to mount on the stock rim with the rim locks, but they need to be used, and it can be done. I now run a 120/90V18 on the rear and frankly it works just as well as the 130. I believe this is because the 130 is so wide that the profile is deformed when being squeezed onto the narrow stock rim. From now on I'll stick with the 120. Ed

The bike I bought had the mag wheel on it. Sorry, I don't know my 650's that well. (not at all)

thanks for the info guess i will stay with the 120 thats on it