81 kz650 Performace Options?

Hi guys,

Well my ol 81 H1 kz650 was seized up, So I opened her up last night to find that the middle chambers where all rusted up. So since Im going to have to have it honed out, Im open from some performance Ideas.

I have a friend who said the could hone it or bore it for me, didn't matter to him. So Since I only have the motor and this is just a project, I would like to hear some ideas on this? Iv seen that people are putting the kz750 pistons in the kz650 alone with the cams as well. This sound interesting. Doeas anyone know what type of HP with would make?

Any Ideas would be great. Like I said this is just for fun, so even if it takes me a while to get the parts, its no biggy.

thanks for the ideas
Daryl

Well, with 750 cams and pistons you pretty much would have a bone stock 750, which makes hp in the 75-80 area. Although power differences may be slightly different because of the differences is heads.
I had an extra set of 750 pistons laying around and started a thread on here about boring my 650 cylinders out to fit the 750 pistons and I was told that the cylinder sleeves would be too thin and you would have to get a set of 750 cylinders. Although if you were truly looking for performance, wiseco makes a great piston set for the 650's and 750's. They are high compression(10.25:1) big bore pistons.
For the 650's they are-are 700cc (used to be 715cc i believe), If you went with the 750 cylinders you could get the 810cc pistons.
As for cams, the 750 cams are better than 650 cams. Although once again if you are truly looking for performance you need to find a pair of 83-85 gpz 750 cams. MAKE SURE YOU GET CAMS FROM YEARS 83-85. If they are any earlier than that they are the same as the kz750 cams.
There are a few places where you can find aftermarket cams for these bikes but they are expensive and hard to time.(what i have heard, i have no direct experience with aftermarket cams)