i have a 2006 kfx 400 with a Two Brothers slip on pipe and a K&N air filter and it is running with the stock jet. i have the jet that two brothers sent that is supposed to be used with airbox lid off. i was wondering if i put the jet in now would it give me a boost in power and would it make a bigger difference when i get a breathable airbox lid?

 

I know this much, your running your engine lean w/o the jet installed. Just by you installing that slip on will increase the exhaust flow. In return , the engine will suck more air. The main jet thats on there now isnt big enough to supply the proper amount of fuel to the air mixture. I honestly can't say if it will give you a boost of power since I did my filter/exhaust/jets all at once. You will definitely notice it when you put the breathable lid with the jet. Hope that helps.

 

no that helped thank you, just as and after though how much would a 3 curve cdi help performance?

 

<div class="FTQUOTE"><begin quote>Originally posted by: RealAceRider

no that helped thank you, just as and after though how much would a 3 curve cdi help performance?</end quote></div>

Now that, I wont be able to tell ya!!!! I got a procom. Its suppose to be a POS. I have had it for over a year now with no issues(knock on wood). I imagine a cdi with 3 curves would do ya just fine. Its a matter of personal taste of whick curve you like the best. Also what riding your doing. It should bump up the rev limiter between 700rpm-1000rpm. I had to get the cdi because I like to shift at a high RPM. The stock cdi would cut out right when I was about to shift the damn thing.

 

the one i am looking at is a procom also. it has 3 curves: one for low end one for mid range and one for top end. then it has each curve repeated with +1000rpm and +2000rpm. i would have it set for low end and plus a 1000rpm. i would need the low end because i am getting a bigger front sprocket to gear the quad up so 1st gear is a little more usable and not so small

 

<div class="FTQUOTE"><begin quote>Originally posted by: RealAceRider

the one i am looking at is a procom also. it has 3 curves: one for low end one for mid range and one for top end. then it has each curve repeated with +1000rpm and +2000rpm. i would have it set for low end and plus a 1000rpm. i would need the low end because i am getting a bigger front sprocket to gear the quad up so 1st gear is a little more usable and not so small</end quote></div>

Yea, Im kinda in that position myself. My first and second gear are pretty much worthless after I installed the cam and did the head work. Im waiting on a rear sprocket(38T) to come in. Hopefully that will help.

 

i would say getting a 25 pilot jet and an adjustable needle jet to go along with you main would be the best bet for your power increase

the whole idea for airflow mods such as you ehxaust and removing the lid is so you can run bigger jets for more fuel


also a lean engine is not a happy engine

lean=heat

 

i know running it lean is bad that is why i have the stock box lid and not breathable one on bc the jet is made for the pipe and lid removed. 38T should help some. i think i will stick with the jet they gave me kfx400kid. my least favorite thing is to mess with the carbs. just a little to much rich dont run for crap and run it lean and you end up with a blown motor. had a 400 scrambler that ended up a 440 by the time i got rid of it granted that was a 2 stroke