carb info?

[honda380]

i got a stock carb and a 38mm carb, not an airstryker, just 38mm keihin. if i want to race, which would be better assuming that i set them up correctly. i was under the impression that the smaller one gives better low end and the bigger one gives better top end? someone set me in the right direction! thanks, Corey

[racerx573]

Most guys (including myself) will run a 36-38mm carb for MX.. for engines 250-265. I have a 265 PV and run 39mm carb because the powervalve helps with the bottom end and the 39mm carb with it lets it run like a mother in the top end.

I also run the same carb (rejetted) on my 275 back up engine.

I believe the stock is a 34mm. I would get that 38mm jetted for your engine and run that bad boy.

What kind of pipe/reed cage (and spacer)/filter are you running, also is your engine ported? If so by who?

You have the right idea with the smaller carbs helping out in the bottom end and vis versa with the larger and top end.

Chances are you have an aftermarket pipe, so regardless the larger carb will help since you have more exhaust being allowed out, so the larger carb will help it out by allowing more fuel and air into the engine.

On my 265 PV & my 275 non PV, I run a Sparks MX pipe, V-Force II reeds with a 1/4" spacer, 39mm carb and a K&N filter with outerwear. Both engines have a llong rod ('89) crank, and an '86 style piston with the spacer plate.

What style crank/piston are you using and do you have a spacer plate?

[86 Quad R]

as stated by racerx573 . its important to know what pipe, reed cage, intake and porting you have. what riding style you do mostly? all these things are important when selecting a carb for your engine. installing the wrong carb can unbalance the power delivery drastically. :eek:

[CorvetteZ06]

get the right setup, and run the 38.

[honda380]

i have a long rod/spacer set up, vforce2 cage, aaen pipe that i have yet to try out, k&n filter, i cleaned up the ports a little, nothing drastic. and i usualy ride fast trails but want to hit the track some. changing and setting up the carbs isnt a problem. jetting is a hobby of mine i guess. thanks for the info! Corey

[86 Quad R]

you'll enjoy the pj 38.