HMF Exhaust ? need help for this weekend

[450Rfutureracer]

well i just bought a new full sport series hmf exhaust and put the 152 main jet in and it runs like crap. i don't know if the air fuel screw needs to be changed or a different jet. its a stock bike besides it has a KnN air filter

[zje400ex]

it depends what year your 400ex is. here are the jetting specs on the 400ex with a full hmf exhaust.

1999-2003 Full System 180/200 Keihin Hex
2004-Up 152 Keihin Hex/42 Pilot

with my slip-on i turned the air fuel screw all the way up and it runs great.

[450Rfutureracer]

its an 07 but the air fuel screw is pretty easy to get to and take care i havent had a chance to look at it

[zje400ex]

when i jetted mine i rode it w/o turning up the air fuel mixture and it didnt run as good as it did after i changed it.

[400excaleb]

i got the same set up, and i got a 150 main stock pilot and fuel/air screw is a little over 2 1/2 turns but ull just have to st it and ride and adjust and mine is about as perfect as ur gonna get it. it could start w/ out the choke on in the freezer

[tanner 222]

i would try a 160 main jet and 42 pilot. i have the same set up on an '07 bike and mine couldnt run any better. havent touched the air screw either.

[400excaleb]

well the first thing u need to figure out is if ur gonna leave the air box lid on of off