Join Date: Jul 2003
Location: Sydney, Australia
Motorcycle: GSXR1100 WS
Re: 750 gearbox in 1100 engine
750W gearbox willl fit in 1100W cases . . . you just need to use the selector drum, selector gear shaft, and selector forks to match. You can modify the late series hollow 750W shafts for hydraulic operation. You cannot use the 750W clutch with the 1100W, because the basket fouls the crankshaft and conrods. The 1100W clutch can be used after some machining because of the shorter clutch shaft on the 750W. The 750W gearbox is much weaker (not surprising) than the 1100W's. Some racers made the swap to get the closer ratio's for the track, but really with the high/broad torque available on the 1100W's it is not an issue. My race engines pull hard from 6000 to 11500, and all I have conceded was to get a Robinson 2nd gear ratio to reduce the split between 1/2 and increase the 2/3 split for track work.
Streetbike . . . GSXR1100WS, Yoshi RS3 pipe, Factory Pro jet kit. Hillclimb car . . . 1298cc SBM big block, Yoshi stage 2 cams, FCR41's, Dyna 2000, MTC lockup clutch, Geartronics paddle shifter. Circuit race car . . . currently 1145cc JE kit, but building 1118cc Wiseco Gixxer with Hahn Racecraft EFI turbo.