KZ400 6-speed in KZ750 twin??

I have a 79 KZ400 with a 6-speed tranny in it and I was wondering, would that transmission fit into my KZ750B3?? I realize that I would have to change shift drums but would it be a direct bolt in. I know that the overall gearing wouldn't be that much different but it would make for alot of fun. I'm thinking about tearing it down and rebuilding it this winter anyway so i figured as long as I'm there...

After looking at the transmissions on the parts diagrams at kawasaki.com, I don't believe the KZ400 trans will fit the 750 twin.

It does look like the 550 six speed would probably fit the 750 twin though.

Wow, I didn't think that the 550 would. I thought that the 550, 650, 750's all shared a platform and that the 400, 440, 750 twin's kind of had a similar platform. Well I guess I'll start looking for a 550 then. Thanks for your help.

I thought the same thing, but when I started looking at kawasaki.com I noticed that all the 750's (twins and fours except the Turbo) use the same transmission bearings (didn't check all the bearings though), and the 750 twin shares the output shaft with some other models that the 550 output shaft will work in. The output shafts won't share the same part numbers because the 550 uses a different sprocket retention method.

This is based on a cursory search through the part numbers, if I was contemplating installing a 550 trans in a 750 twin, I would certainly do a more detailed comparison.

I believe the 750 four and the 550 output shafts will interchange, I even bought a 550 shaft drive transmission (because they're cheap, no one wants a shaft drive trans) to try it and see if it works. Haven't got a around to it yet though

Hey Steell!

Did you ever get the 550 shaft tranny workin?

Spot

one of the two shafts does fit of a kz400 (prebike of the 440)but I do not know if it was the drive or clucht..

Out of curiostity what would be the advantage to having the 6 speed trannie in the 750twin.other than it being a 5 speed.more top end? would a kz or gpz550 6 speed trans fit into a 78 kz650c then?if so what years.thanks
Regards Paul