[arsenic]

well, I'm gonna have to concede here. I can not prove that the 1990 is the same crank. All the cross reference do say that the Katana 750 and 88-89 GSXR 750 are the same. To shed a little light on your question, the 88-89 GSXR 750 is the short stroke "slingshot" motor, it has the most HP out of the box. The pre 98 Katana 750 is also a short stroke. So I imagine the crank has the cut to accomadate the most HP.

[ericej2344]

Great news for me. I found out that the primary drive gear is straight cut. Now back to my plans for a BIG horsepower katfighter. Thanks to all for your input.