A race system doesnt always mean you automaticly have to go richer, my tyga pipes i infact had to drop 1 main jet size smaller than stock to get them to run right.
Bill who uses stock pipes for racing is always up over 190m/j though and always has to drop them when using his racing gibbsons, which of course make less power and torque but do over rev alittle better.
As for the stock honda cans, after market ones do help alittle. On back to back runs a set of race cans pick up around 1.5 to 2bhp over the stock cans and seem to need alittle more fuel.
The best set up we had with Bills was stock chambers, swarbrick cans, no air box, hrc jet kit and wire splice made just under 66bhp. Not bad for a stock motor. Even my 18 made 60bhp once it was set up right with stock cans and chambers.
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If I have to take the carbs off once more...