400ex re-jet

[quadmad16]

i' ve recently purchased a sr4 motorwoks slip on exhaust for my trx400ex....is it necesary to re-jet the carb for just a slip on...


i need help?!?:confused:

[BEAVER.989]

Absolutley. I can't tell you which jets to run for sure(not familiar with your area, elevation, etc.), but it should be somewhere in the neighborhood of going up one or two sizes on both the main jet and pilot jet.

[quadmad16]

what about a stock 450 carb???

[BEAVER.989]

Originally posted by quadmad16
what about a stock 450 carb???

I don't have any info on the 450R carb, but if you read the very long and detailed sticky on it, it should tell you everything you need to know and then some.

[omeeomy]

i went with a slip on and didnt rejet mine runs great
just messed with the air fuel screw to get it not hesitate
my mech. told me i didnt need to and it runs like a top
but i guess if ya wanted to you could
he also said that you would deffanately if you went with a full system so idk

[quadmad16]

but omeeomy did u have any noticeable gains in power??

what pipe did u get??:)

[racerdan24]

Originally posted by omeeomy
i went with a slip on and didnt rejet mine runs great
just messed with the air fuel screw to get it not hesitate
my mech. told me i didnt need to and it runs like a top
but i guess if ya wanted to you could
he also said that you would deffanately if you went with a full system so idk

Same here...sometimes you do not need to rejet when you just add a slip on....play with the air/fuel to get it close....

[RIDEREDson]

but... you may not be getting the full potential that the slip on can give you. Go up a size or two on the main.

[racerdan24]

Originally posted by RIDEREDson
but... you may not be getting the full potential that the slip on can give you. Go up a size or two on the main.

You are 100% correct on that....have i jetted mine since adding my T4? No....i haven't. Am i getting every ounce of power...no...but i have been lazy i admit it...i have the jets,just to much work and not enough time to do it....i squeeze a day per week to ride if i am lucky. i should take Nike's advice...JUST DO IT!

[omeeomy]

yes i noticed big gain in low end
i got the DG krome lite race pipe
it takes disks like a supertrapp
but i did do a cdi box and k&n with pre filter also so it all came together real nice
i just adjusted the air fuel screw in a half turn and WOW

[Gibson]

Get a 150 and a 152 main and try both of them, and also get a 42 pilot and it'll start way easier. And you might have to adjust your needle for fine tuning, but i think it'll be spot on.

I'm running a 150 main, 42 pilot and the needle on the 2nd notch from the top and my a/f screw 2 1/2 turns out. It runs awesome. The only thin you might have to adjust is the a/f screw

[omeeomy]

mine is all stock motor wise
so i dont think itll work for me but you do have nice starting points for modded motors