Smoothbores are the biggest bang for the buck with that motor. I'd go with 38 RS.
For the swingarm, you want to find one from a '95 GSXR 750 which is a factory braced unit that is about 10mm shorter than the 90-92 750 arm. The only downside it that that swingarm uses a larger pivot tube and you will have to have a spacer cut for it and run another set of the inner needle bearing races from your old swingarm in the '95 to sleeve it for your smaller axle. It is very simpe and it bolt on with the exception of getting the inner race bearing spacer cut. You will also need the draglinks and rocker arm and the rear caliper as it mount differently.
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For the swingarm, you want to find one from a '95 GSXR 750 which is a factory braced unit that is about 10mm shorter than the 90-92 750 arm. The only downside it that that swingarm uses a larger pivot tube and you will have to have a spacer cut for it and run another set of the inner needle bearing races from your old swingarm in the '95 to sleeve it for your smaller axle. It is very simpe and it bolt on with the exception of getting the inner race bearing spacer cut. You will also need the draglinks and rocker arm and the rear caliper as it mount differently.
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