gsxr slingshot carbs - will the swap over to a 750 Seca?

Got a chance to pick up some early gsxr750 36mm carbs dirt cheap. Its a bit bigger carb and who knows how the bores line up but I'm wondering if it is worth a try...

To be specific, these are the 36 mm Mikuni constant-velocity semi-flatslide carbs from the 1988 Suzuki GSX-R 750.

 

They won't be a direct swap. You'd have to make boots for them since the outer diameter has to be larger for the OD to be 4mm larger. I don't think the stock boots will have enough stretch to them to keep the carbs in place without risking them popping out. I'm also pretty sure that the carb spacing won't be the same.

Then there is the matter of the larger throat. You'll be reducing the velocity through the carbs compared to the 32mm Hitachi's. This will mean that you'll be playing around with jetting, and maybe not getting good results. I do think that it's worth doing, particularly if you are wanting to overbore, or swap in a 900ccc mill.

 

Yeah, I figured I would need new boots at the least. The spacing I figured I could maybe build a custom rail, or machine some adaptors (which would also help with engine side mating). A 32 mm throat has 80% area of a 36 mm, so that doesn't seem to bad ... and leaves me a nice margin to play with if I ever want to try for a blow-through turbo.

You are right though, its probably not worth the hassle, especially if I want it ridable any time this year (hopefully by September, ideally by July).

 

A 20% difference in area makes a big difference in flow rate. Consider that even though the GSXR mill is the same displacement, it breathes much better, and revs higher than the Seca. I do think that they could work nicely, it'll just be a fai amount of work and you may sacrifice some fuel economy.