lean or what??

[finsteratv]

we bought my mom a 2007 400ex about 2 monthes ago in near mint condition probably 5 hours on it tops. after a few small day rides the head pipes look blue right near where they come out of the engine. im pretty sure this is a sign of being lean?

[honda400ex2003]

imo it is not a real big deal but it may be a bit lean. whats your elevation and such fin? it may be worth while to go to a 42 pilot and a 150 main if you are really close to sea level since it is getting cooler outside. steve

[honda400ex2003]

also does it get any better if you put the choke on? that would show if it is going to help or not by richening it up. steve

[CJM]

I find almost all of them come lean from day one. Try adjusting the air/fuel screw on the bottom a turn out or so and see if it runs better.

[finsteratv]

it runs just fine just like my 05. its just the header pipes bluing

[CJM]

Originally posted by finsteratv
it runs just fine just like my 05. its just the header pipes bluing

Oh they all run "fine" but your header pipes turning blue means its getting slightly too hot which means the bikes a bit to lean.

[finsteratv]

thats what i thought
i guess ill play around with the f/a screw

[CJM]

Turn it all the way in then count the turns out. I would try 1.5 turns out first and see if that helps. Still gets really hot turn 2-2.5 times or so. Anything more than 3 turns means you need to step up to a larger jet.

[finsteratv]

alright ill try that out
thanks for the info

[honda400ex2003]

imo you would be fine going to 3.5 turns out without needed a new pilot. anything more than that and you would have to go up a size or two. 2.25 turns out is stock setting, you wont want to go leaner than that. it would just make it worse. I ran my stock pilot at 3.5 turns out for years with no issues. steve

[jensenracing77]

i put 42 pilot jets in almost all stock 400EXs. almost always able to leave the pilot screw alone with the 42 pilot. the EPA has them running more lean than i like. most likely you don't have a problem that it going to hurt anything but i would go to the 42 pilot. if you don't want to pull the carb then just turn the pilot screw out one turn. it won't hurt. all the above is based on if nobody ever messed with it in the past.