Jetting??

[KASCHAK]

I have a k&n air filter and im getting a full t-4 pipe what jetting should i do to it so that it runs right. my temp. is about 60-90 when i ride and my elevation is 1900 any thing else i need to tell you? thanks for you help

[toby400ex]

with airbox lid on, 155 main if they are keihen jets, if it is dyno jets then it will be maybe a 146 just like mine. With the needle clip on the third notch and the mixture screw 3-3.5 turns out

[KASCHAK]

what is the difference between those jets? and what does taking the needle clip 3 notch do? im not real good with carbs but i want to learn alot about them so im askin alot of questions

thanks

[White_Knuckles]

The jets differ by bore design. Dyno's and Mikuni have a more tapered bore design and claim to have a more efficient spray etc., this is subjective. The sizing is measured for Dyno and Mikuni by jet CFM flow rate where a 140 flows 140 cubic feet of air/fuel a minute. Keihin uses actual bore diameter of their scale.

Usually the Keihin equivalent is one size smaller than the Dynojet. Sizes go in increments like 150, 152, 155. So a 150 Dynojet would be close to a 148 Keihin.

An average rejet for the 400 is (Keihin) 152-155 main and a 40 pilot for your altitude. Don't go for the big numbers thinking a big-ol-jet should make for a screamin' ride. You'll drown the thing with fuel, bigger is not better unless you have other mods to use it.

Learn to troubleshoot by plug reading and lean/rich symptoms that you feel riding. Dial it in from your tests.