A 40.5 carb is not enough for a serious running 330 or a middle of the road 370.
I prefer to use Mikuni carbs for alcohol because they have 3 more tuning circuits than the PE, PJ or PWK series of Keihins carbs. The Mikuni carbs are designed so that the needle jet can be changed to various sizes, the float valve seat can be changed for different fuel pressures and flow rates and they have an adjustable air correction circuit.
My experience has shown that the additional circuits in the Mikuni carbs gives an experience tuner the ability to get a more precise tune than on Keihin carbs that were designed for the two strokes.
I do not understand why Keihin does not offer these additional circuits for two strokes but offers these additional circuits for the off road four strokes as well as the carbs they make for the street type engines. All of the after market Keihin needles for the PE, PJ, or PWK series of carbs are single taper needles. The reality is most engines need needles with at least two tapers and sometimes three. I think that Keihin must have assumed that there are not any seasoned tuners in the off road world and thought it would complicate things or add more confusion for us dirt goons.
