Jets!!! So Many Wich One???

[steveatv3]

OK i have a HOnda 400ex,

I bought a WB e-series pro-meg slipon
*K&N filter
*AND AN ASSORTMENT OF JETS

my question is what size MAIN jet should i use with the pipe and filter???

and should i screw around wit anyonther jets, or adjust that metal washer thing on the needle jet??

[cals400ex]

i am assuming you bought keihin jets?? if so, i had a similar setup as you and i ran a 158 mainjet. the bike seemed to run good. we need to remember jetting is just trial and error. i would also go up on the pilot jet. a 42 or 45 pilot should work just fine. i find it best to leave the needle in the stock position with those bigger pilot jets in. however, my bike seemed to run good when moving the clip on the needle down one position, but it only ran good this way in the winter months where you need a richer setting.

[steveatv3]

could i put a 162 main jet and leave the pilot the same

[trailburner]

Originally posted by steveatv3
could i put a 162 main jet and leave the pilot the same
sure .....why not. I run a 162 main in the summer & 165 in the winter...runes great!! our mods are allmost the same..

[cals400ex]

Originally posted by steveatv3
could i put a 162 main jet and leave the pilot the same

your bike may run fine with the 162 in, but i bet that is a little big for best performance. why do you want to do that though??? the pilot jet is for idle to about 1/4 throttle. the needle is for about 1/4 to 3/4 throttle. the mainjet controls 3/4 to full throttle. if your not going to get a new pilot jet, i would at least turn the fuel skrew about 3 or 3.5 turns out. i think that is as far as you are suppose to go on the fuel skrew.

by the way, how do you have a promeg slip on? the promeg headers are bigger than the stock ones so there is a bigger inlet on the silencer for the enlarged headers. this silencer should not work with the stock headers if i remember correctly. maybe you just have an e-series slip on??

[steveatv3]

OK now what do u recomend.

main jet 162
with 3 turns down on the gas screw??


will i notice a big differents with the jets?

[steveatv3]

ok what do u recomend?????

jet size, and needle gas adjustment?


should i get a new pilot?? what size???

[trailburner]

In the manual that I got with my pipe[E-series] it says you don't have to do anything with the jetting if you are runing stock[filter with lid on]but you are runing a K&N so to be safe I would go like 2 sizes up on the main thats it......

[cals400ex]

if i was you this is where i would start:

155 keihin mainjet
42 pilot (this is not manditory, but will prevent your bike from running lean)
with the 42 pilot in, about 2.5 to 3 turns out on the fuel skrew
leave needle alone


good luck

[steveatv3]

Ok this is what i think im gonna go with,

I think im gonna go with a 155 main jet and not screw with anything else

this is the same jet that they ran doin a dyno at DIRTWHEELS on the E-series

what do u think, do u think i should go with it?

[dariusld]

You could do it your way and see how it runs. I think alittle closer to being right, would be the 155 main, pilot screw 3.5 turns and adjust the needle clip one position. Thats what I would do.

[steveatv3]

thanks dude, im gonna run it with just a 155 main, then im going to do what u said

[pnut420]

Originally posted by steveatv3
Ok this is what i think im gonna go with,

I think im gonna go with a 155 main jet and not screw with anything else

this is the same jet that they ran doin a dyno at DIRTWHEELS on the E-series

what do u think, do u think i should go with it?

I would LISTEN to cals400ex, do a 155, 2.5-3 turns out, and for sure a 42 pilot, the worst thing for your engine is running lean, it was ruining mine.

And remember just cause your bike is running good and fast, doesnt mean its not running lean. Mine was way faster when I ran it lean, then it started loosing more and more power. Rings probably fried.

[steveatv3]

THANKS im gonna do that!

[cals400ex]

yes, just think when you are at less than 1/4 throttle. you will be lean with the stock pilot jet more than likely. i am still tinkering with the needle so i can't help you much there. i found it best to run in the 4th position in the winter but in the summer it was sputtering hence it was too rich( the plug also indicated this). i think i am going to try a different keihin needle. however, in the summer mine seems fine with the bigger pilot, stock needle location, and the bigger main. the bike ran good and the plug came up a nice tan color. good luck

[steveatv3]

ware can i get just a pilot jet and not in a kit form,

i know K&K atv has them but i THINK they are only for kehin carbs

[cals400ex]

what kind of carb do you want it for??? if it is yours, you have a keihin on your 400ex unless your are using an aftermarket carb. you can get pilot jets from C&D, your local honda dealer, etc.

[steveatv3]

Thanks dude, for helpin me out!!!!

i got a jet from K&K