engine rebuild

i have a 78 kz 650 that runs good but i just wanted to freashen up a little so i got the cylinders board out for the weisco 700 kit, it already has stage 3 jet kit , full vance and hines exhaust and pod filters on it , i also bougt pretty much everythig to rebuid the top end of the bike , so when done the bottom end is stock orginal with 22000 miles on it the top end will be rebuilt with stock parts i got from Z1 enterprizes with the 700 kit.then i thought about turbo charging it , there is a used kit on ebay right now that is a ATP kit with a rajay turbo model# 377B25...So im i nuts for wanting to do this , also the price is around $670 is this a good price or does someone know of a place thats makes a kit. if this is possible what would i have to do and or change...any help from anyone would be greatly apprecited....Also i want to up grade to a inverted style newer front end forks does any one know what will work i know mods are going to have to be made i just need a good starting point on both of these subjects any and all help would be great .....Thank you

Well, you need to build the engine for a turbo, the 10.25:1 compression wiesco pistons are not the best idea if you want to put a turbo on it. You would probably want to lower than stock CR, but it depends on the boost you expect from the turbocharger. There are a number of guys here who run turbo bikes on the forum that can chime in on this.

The 650/750 is a strong engine, if set-up properly you can build a pretty serious motor, but it's not as simple as just bolting a turbo on.

I run the 700cc pistons and they do make a bit more torque, you can build a 810 with a 750 top end and many people have done that with great results. Combine oversize pistons with a good cam, proper carburation and good head work you will make the 650 run very well.

You don't have to worry about the cam and porting stuff so much with a turbo. Completely different setup.


Also, I did find some specs on that trubo after looking arounnd.

B25- 180cfm @1.5 pressure ratio at max engine speed 7000 rpm and 7psi max boost.

If you want an air cooled turbocharged 650/750, buy a 84-85 Kawasaki 750 Turbo. If you're determined to roll your own, then at least use a modern ball bearing turbo, like the Garret GT series.