Michigan rider needs help with 400ex and Lexx exhaust!

[RNL]

Hi everyone. I recently got a 2003 clean 400ex for a great price last fall. I havnt had time to do much, if any riding on it but thats about to change. The deal is I just got a lexx exhaust from Rocky Mountain atv. I've never jetted anything before so I was wondering if anyone had any recomendations, starting points etc., or if anyone else is running this exhaust and could share their setups as far as jetting. Or would I just be better off to take it to a shop? Thanks!

[dalejiw25]

If all you're doing is adding a slip-on pipe you prolly don't have to rejet. If you are adding a complete exhaust w/ header and removing the air box lid and adding a K&N or UNI, you need to rejet. If you are uncomfortable rejetting yourself and decide to take it to a shop try to find one with a Dyno. Getting it Dyno-tuned is the only way to go. It is spot on. Also add a sig Similar to mine about your Quad it will help us all to know what you are dealing with.

[omeeomy]

i added a slip on and a k&n with outer wears
left the air box lid on
i didnt need to rejet

[RNL]

Originally posted by omeeomy
i added a slip on and a k&n with outer wears
left the air box lid on
i didnt need to rejet

Well I just pulled the plug and its white........so its running lean without the pipe even on yet. So jetting is a must for me now.

I see your in Montrose, I'm down In Fenton. Nice to see some local guys on here.

[RNL]

Originally posted by dalejiw25
If all you're doing is adding a slip-on pipe you prolly don't have to rejet. If you are adding a complete exhaust w/ header and removing the air box lid and adding a K&N or UNI, you need to rejet. If you are uncomfortable rejetting yourself and decide to take it to a shop try to find one with a Dyno. Getting it Dyno-tuned is the only way to go. It is spot on. Also add a sig Similar to mine about your Quad it will help us all to know what you are dealing with.

Its got a Uni filter on it right now, rest is stock. I was gonna just add the slip on and take the lid off.

[omeeomy]

yea im up here in the sticks lol
if you have face book come join us at
MIDMICHIGAN DIRT RIDERS
lotta good peps ont here

[f4iracer]

I've got a 2007 ex with a uni air filter and a lexx slip on

i"m running 2 sizes bigger on the main jet which is a 152 main.

and i've got an adjustable needle that is on the 3 clip down.

Your ex should have an adjustable needle....don't be suprised if you have to richen that needle up a little.

i'm in illinois but my quad ran like crap after i did the uni filter and lexx slip on mods, i had to rejet that's for sure!