Does any body know the best carb size for the xs, after market slide carbs not the cv, I've read about some racers going as large as 38mm, but with only a 34mm inlet track is this a waist? or will it compress more gas into the cylinder as it passes?
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optimum carb size
- Thread starter jay760
- Start date
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- carburetors
Yeah, 38 mm. carbs are used--in drag racing and on fast road race tracks. In much dirt track racing and on tighter road race tracks, 34 mm. carbs are favored by many tuners (note that Shell Thuet was an exception here; he favored 38's even on short track machines). Port diameter isn't the main factor. The larger the venturi, the weaker the vacuum signal becomes. Bottom line: while you can tune 36's and 38's to be streetable, they won't buy you anything more than what's available from a pair of 34's on a punched out street tuned motor. If you want stats on that, go to 650 Central, click the link, and buy a copy of Craig Weeks' performance tuning manual.
