Re: Does intake size affect jetting?

OMG ... let’s not get in to this to much deeper .. if the hole going in to the cylinder is 20 mm sticking a 18mm or 16mm carb on is not going to make the bike make more power or go quicker..

putting a 24mm carb over an intake tube or hole that’s 20mm don’t help either.

needs to flow smooth from out side to in ..

Air filters are another storie ..

A RD400e air box that’s like 3 boxes bolted to geather can work better than the 2 KN pods guys put on if jetted right ..


Re: Does intake size affect jetting?


Re: Does intake size affect jetting?

Probably Fred /

> Chöschi21 C.K. Wrote:

> -------------------------------------------------------

> Just think about it, you are restricting Flow to your Engine, what do

> you think would happen with the Jetting?

Totally agree we-got to jam sometime!

Re: Does intake size affect jetting?

So I don't know that anyone addressed the actual question, at least not directly. While everyone's discussing the effect of carb bore on jetting, the question was about the relationship between intake and carb mismatch

my intuition without doing any specific research besides past experience, and aligned with some of that's been said, is that:

a smaller intake than carb creates a restriction after the carb (speaking in direction f fuel/air mix flow). that restriction reduces the vacuum, maximum velocity occurs in the restriction (intake) not at the carb, and the carb behaves like a less effective carb of roughly the diameter of the intake minimum bore

a larger intake than carb just creates a dead volume but probably doesnt hurt it much. I mean when you're not at WOT, your carb's effectively smaller than the intake anyway. I'm sure it affects resonance, mixing, turbulence etc but I don't expect it to be a huge effect. though I have noticed when you have different diameters, like step changes, you can get gas pooling especially at idle that makes a stumble when you open up.

Also that might be likelier to ice up?

that actually seem correct?

Re: Does intake size affect jetting?

Angry Hipster /

Thank you! Finally the question has been addressed.

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