Intake Manifold Shorter VS Longer

circleball · Jul 13, 2013

A shorter intake manifold will be leaner (less gas) than a longer intake manifold, richer (more gas)

(i had been curious and found nothing on the matter in plain, easy, straight forward answers. So here we go.)

for example: if you have the smallest jet you can find and already tuned the carb with the needle (if you have one of those carbs). and you are still a bit rich on the mixture, try using a shorter intake manifold, and vise versa.

crassius · Jul 13, 2013

only thing I know for sure about manifold length is that if your engine vibrates a lot, a longer manifold will foam the fuel in the carb bowl & make the engine sputter

biknut · Jul 13, 2013

circleball said:
A shorter intake manifold will be leaner (less gas) than a longer intake manifold, richer (more gas)

(i had been curious and found nothing on the matter in plain, easy, straight forward answers. So here we go.)

for example: if you have the smallest jet you can find and already tuned the carb with the needle (if you have one of those carbs). and you are still a bit rich on the mixture, try using a shorter intake manifold, and vise versa.

Who told you that? The length of your intake manifold won't effect the jetting much, but it will have an effect on your powerband.

maniac57 · Jul 13, 2013

More volume in the intake tract usually helps low end power and smoothness in small piston port two strokes. It seems to give a ram air effect when the air column slams into the closing port.
Bigger/longer intake=better low end.
Unless the engine is highly tuned this is a good rule of thumb.

bairdco · Jul 13, 2013

i've always found that the shorter the intake, the faster your bike goes, plain and simple.

F_Rod81 · Jul 26, 2013

I prefer the shorty intake... Most of the aftermarket intakes that are sold now have a spiraled plenum. They atomize the fuel charge better and the result is a smoother, faster running engine. Plus they just look cooler then the stock manifold! (^)

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Intake Manifold Shorter VS Longer

circleball

New Member

crassius

Well-Known Member

biknut

Well-Known Member

maniac57

Old, Fat, and still faster than you

bairdco

a guy who makes cool bikes

F_Rod81

Dealer