headder pipe glowing red at idle?

[ranger400ex1994]

I just had my motor done about a month ago and the guy that did my motor said that a 406 jetting would be about the same as it would be with my stock motor with the FMF system. now yesturday I went out and started my quad and the headder pipe started glowing red. then i let is idle some more and the pipe went back to normal color but then i reved it up and it became red again. my jetting is a 150main and a 42 pilot. i called the shop were my motor was built and they said to try 152main and a 40pilot or leave the 150 in and go down to a 40pilot. what do you guys think?

[nosliw]

really lean.

check where the headpipe meets the block, maybe it isnt in right or the gasket is crap :confused:

[kicken250x]

i agree...waaaaaaaaaaaaaaaaaaaay lean. stick your hand up where the pipe meets the head and make sure you dont feel any exhaust blowing out. if this isnt it you need to go UP on your pilot jet to get more gas in the motor and richen it up some. id go up about 2 jets from where your at. thow a new plug in a check to see where your at

[fastkid400]

yeah do a plug check, if it is as white as heaven then ur lean as hell, go up on ur pilot jet size

[cals400ex]

were you running keihin jets?

if it is glowing at idle, turn your fuel screw out (counterclockwise) a little bit.

if it is glowing when you hit the gas and stops glowing after it idles for a second, lower your needle clip.

good luck

i figured that main would be a tad small to but the dyno said your tuned in.

[ranger400ex1994]

ya i don't know what the deal is. yesturday when i started it up it was about 50 degrees out from being about 65 or so the other day so i don't know if 15 degres would make that big of a difference. and there are no exhaust leaks.