I see that adding and 38mm carb can add 2hp, according to RCR, HPD etc... What size does the stock 34mm carb on a Scrambler 400 end up being if it is bored? How does the hp gains compare to paying the extra cash for the new aftermarket carb?

Also, anyone know how much power is added with porting for trail-type use? I am trying to decide what type of mods I may or may not get.

Thanks for the help,
PowerHungry

 

A larger carb will gain you nothing without modifications. The more mods you do to your machine, the more the carb will make a difference. If its mildly modified or stock, you would have very little to gain from any carberator change. If you have say a pipe and silencer, porting and polishing, higher compression etc, then the carb would be the next step. I would get a new aftermarket carb over messing with the stock one. Usually the aftermarket ones are just designed better as well as available in a larger size.

 

PowerHungry,

The stock carbs can be bored to 35.5mm. For me, it ain't worth the money.

True the 38mm carbs do give you only 2 horsepower, but the throttle response is like a light switch compaired to the stock carb. Throttle responce is MUCH quicker than stock.

I wouldn't even consider adding a larger carb to a Polaris machine that isn't ported. The transfer ports are WAY too small for it to work properly. Trust me, I've learned from experience. The best thing to do would be to save up and get it all done at once. New carb, reeds, porting, head mods and pipe. You won't believe it's the same engine after the mods.