KZ650 6 speed Conversion

I'm trying to track down information on fitting a KZ550 or GPz550 6-speed
gear cluster into a KZ650 engine. Seems, a few people on the Net have heard
of it being done but no definite information.

I read somewhere that Cycle World did any article on the conversion some
(many ??) years ago but cant find any info on it either.

Anyone got some first hand info to share ??

 

"Subject: KZ550 6 speed in a KZ750 update "
http://www.google.com/[email protected]

Chances are pretty good the KZ650 cases are the same dimensions as the
KZ550 and KZ750, but YMMV and good luck.

Having owned both a '82 GPz550 and a '77 KZ650, I'd say there's little point
in doing this conversion, unless you have a KZ650 with a broken gearbox and
you already have a KZ550 transmission to replace it with.

 

I am in the process of doing this with a KZ750. It seems as if it will
work, I have the 500 6 speed all assembled in the cases, the only
difference is that the shaft the clutch is mounted on is shorter than the
750 shaft by about 1/4". I have several options, bolt it all up and hope
for the best, machine the inside of the clutch basket so that the clutch
nut is grabbing the same number of threads as on the 750 shaft, or reduce
the width of the clutch nut. I will probably have the inner clutch
machined.

You will need a complete 550 transmission, both shafts, all the gears and
the shifter drum and forks, and you will have to mount the 550 engine
sprocket which uses 530 chain. You keep the engine idler shaft and the
original clutch in the case of the 750 YMMV. I got the complete 550
transmission on ebay for 35 bux including the shifter mechanism, which
appears to be identical to the 750 and the engine idler shaft which uses a
much smaller hyvo chain from crank to idler shaft, and presumably a smaller
clutch as well, the only part I did not get.

Should work for the 650 as well, as it is basically the same motor as the
550 and the 750 from what I understand.