KZ 650 crank mods/swap

The forum debating the weak point of 650 bottom ends suggested the 750 crank may be stronger and a direct swap but nobody arrived at a final answer.
What options other than falicon supercranking are available?

Is the GPZ crank indeed superior?

I have read the rod journals in the GPZ750 are the same as the 900 allowing the use of performance rods.

Is the 750 crank interchangable with the 650's?(other than the hy-vo cam chain of course)

Does the 750 use solid bearings like the 650?

Are there any other cranks shafts that could be machined to fit the 650 casings?

Thanks for any suggestions.

According to buykawasaki.com, the 80 KZ650 and the 80 KZ750E use the same rod and main bearings and the same rods, so I'd say it's a safe bet that the only difference between the two cranks is the cam drive sprocket.

First time I have ever heard of the KZ650 bottom end being weak by the way.

The GPz750 uses the same rods and bearings as the 650, so if 900 rods fit on the GPz750 then they will also fit on the 650. I believe I read somewhere that GPz900 rods might fit, not the earlier Z1 or KZ900 rods. I have no idea whether they will or not though.

Post edited by: steell, at: 2006/09/06 22:12

The problem is soft rod journals. You can have the crank nitrided to make it harder.

Contact us if you want to do this.

www.racecranks.com

Jay