650/750

redhawk4 wrote: I've been thinking about making my KZ650B1 into a 750 or even an 810, in fact I have a complete 2nd motor that I could build up allowing me to keep the original. I've never been able to find a report though on just how much more usable power even an 810 conversion will give, and how it rates on the "Butt Dyno". While the GPZ cams give extra power etc. you are pushing the power to higher revs and I have to say my 650 is pretty powerful already, but we always want more

Goggle "The GPZ modification faq" for a great write up............ some where around 90 HP can be had with et's in the mid to high tens for the right set up....... read Zuk dave's drag race thread for his set up, Kawi810s building one right now, Baldy110 has a beautiful one and more than a few others on here......I've read about 9.8s to 10.03s for several record setting "all out drag" bikes from the old days.

The 1980 KZ750 cyl.block is the only one that will work with
the early 650's roller cam chain but good luck finding one.
Also with the roller chain you have to use a 650 head for the top chain roller.

zukdave wrote: The 1980 KZ750 cyl.block is the only one that will work with
the early 650's roller cam chain but good luck finding one.
Also with the roller chain you have to use a 650 head for the top chain roller.

While it's true that you need a cylinder with the appropriate cam chain tensioner provision, they are not limited to the '80 model year 750. My 81 had such provisions as well.

More info here... forums.kz650.info/index.php?topic=1287.0

Yup I read on here many times that only a 1980 will work till Nessium showed us his 81 block and corrected me. I almost got one from Steele till he decided not to sell a long time ago ..... I then picked up one on ebay but they are hard to find ....sorry keeping still possible I will use it before I die..... but time is running out.

Check out the Bonneville article under file base and search for Bonneville part two also for more hop up info.

If you have the 750 cylinder liners, could you have your 650 block bored to take those liners? I have a GPz 750 block and pistons sitting in my shed and have wondered about the possibility of doing it that way to avoid the need to find the correct year 750 parts to work with the timing chain etc..

There are definitely more years than just 1980 that will work from a 750, but you need to look for the right fittings for the timing chain to be certain, it seems there may have been a situation where some models of the 750 used the older system for longer or the people selling the parts were not accurate as to the year when listing them.

redhawk4 wrote: If you have the 750 cylinder liners, could you have your 650 block bored to take those liners? I have a GPz 750 block and pistons sitting in my shed and have wondered about the possibility of doing it that way to avoid the need to find the correct year 750 parts to work with the timing chain etc..

There are definitely more years than just 1980 that will work from a 750, but you need to look for the right fittings for the timing chain to be certain, it seems there may have been a situation where some models of the 750 used the older system for longer or the people selling the parts were not accurate as to the year when listing them.

MTC used to sell the liners .......was gonna get them and their 831cc piston kit wholesale (just over half the Weisco pistons alone now) from them back in the 80s for a hell of a good price but never came up with the cash ........and they can be bored to fit..... I suppose you could press yours out and have them fitted but wouldn't be cheap anymore.......... from 82 up they used the hyvo chain set up so none from there on work.