This is interesting. Is this a common setup for the GSXR? Seems like it may be a cheaper way to go if you can make it work.

I originally got the idea from another message-board (I think it was the oldskoolsuzuki.info site) where someone used the busa pistons for a turbo-build (makes a low CR). Someone on the maximum-suzuki.com site told me that there's 0.060" available to remove from the tops of the busa pistons which turns them into what amounts to a flat-top piston. I needed rods anyway, and the fact that busa pistons and rods often come together when available as second-hand, well, it was serendipity.

The busa-piston/rod combo is just as do-able on the GSF-1200 platform as any of the older GSXR 1127cc mills.

I was using the 1052-length rods on an 1127 crank previously, which gives a a rod-ratio of 1.98. The busa rods are a tad longer, and with the same 1127 crank stroke, I'll wind up with a rod-ratio of 2.025. ...which will make life easier for the piston-skirts and rod-bearings, but it will tighten-up my piston-to-valve clearances and I'll have to be careful if I want to try to use high-lift cams in it (current build will be with stock GSXR750 "slingshot" (1988/1989) cams and cyl-head).

I'll be sure and let ya'all know how it goes when I get it all back together and take it down the track a few times. Unfortunately for me, that will not happen this weekend as I have had my Saturday day-off revoked due to the boss taking a vacation (not happy about it, but I'll get over it). I'll be riding the bandit (streetbike) on Sunday, and then there's a break in the racing-schedule which will give me two weeks to get everything in fighting-trim on the frankengixxer.

Use the 750 "J" cams, if your cyl head is any good it'll go as hard and not be as hard on the valve train. Thats what I've found with mine.

Al.

It's time for an update! How did these new mods work out??

OK, after spending all day in the garage with it, I have come to the conclusion that the cases or crankshaft or both are bent/tweaked.

I have a selection of bearing-shells, and even using the thinnest ones, the crankshaft binds up and becomes difficult to rotate when the case-studs are torqued. I've had the thing apart and back together three different times, just to double-check everything, and no change.

I'm using the "green" bearing-shells (thinnest ones available) and the crank journal ID code for the cases is all A's and the crank is all A's and I have 0.0008" - 0.0009" clearance on all the journals when I check it with plasti-gage.

These cases and crank are "borrowed" items, so I'm just gonna back up and punt now. Clean everything up, wrap it back in plastic bags and return the cases and crank.

I made an offer on a stock 1157 (bandit) motor on ebay - hopefully that will work out for me.

...or else I'll just be riding the streetbike for the last three race-weekends this year.

ANYway, I'm kinda bummed-out that I couldn't finish this project - but I still have the busa rods and pistons and I will probably make an attempt to build a 1216cc motor with this combination in the future.

Sorry to hear that. I would like to see how this combo worked out. Funny that the owner of the parts did not know the parts were out of spec. I was looking to get a busa motor. Looks like they are real common and can be had for 2-3K with everything. I found two near by. One was newer and less than 2000 miles on it. It came with everything for $3500.

Hope the Bandit one works out. Keep us updated on your progress.