787 Crank interchange?

[Brant]

I just picked up a 99 Gsx rfi 787. The crank is punched. I have a bottom end from a 96 GTX. Can I swap it out with the 99 top end and by'pass the lower cooler? Will the 96 crank swap into the 99 case? Any info would be appreciated.I can't seem to find interchange info..Thanks...BRANT

 

[SabrToothSqrl]

engine

are they even the same engine?

something tells me.... no.

 

[Minnetonka4me]

Its a interesting question...

The crank is the main difference. I have heard of people using RFI cranks in non RFI cases...using the RFI flywheel b/c the taper is different, then using the carb mag cup.

Also...its an old racers trick to use RFI cases with a carb crank on a carb machine to use the case cooler on the bottom.

I would prob refrain from using the carb cases on a RFI motor.

 

[Brant]

Sounds like I could make it work! The RFI case is toast the rod ate thru the bottom into the cooling jacket. Do you think I could use the RFI mag with the carb flywheel? Do the RFI's run that much hotter than a carb model???

 

[Minnetonka4me]

You have to use the RFI cup and flywheel on a RFI machine...I think you would be ok w/o the cooler but im just not sure.

 

[Brant]

I spoke to a machine shop today and I could have the Carb flywheel cut down and use it as a hub for the RFI flywheel. The only possible glitch would be that the ring gear would sit 1/8" farther away from the starter. But I think this could work. What do you think???

 

[99spxxx]

I have rfi case in good shape for $185 shipped...