400ex hard starting when cold (keeps dieing til warm)

[Jon98]

i have an '02 400ex with about 50 hours on it, maybe little less. Its finally warm out, and this winter the thing hated being started, and had to nurse the throttle for like 3-5 mins to keep it running. but i figured since it was so cold, that was the cause.

now it has warmed up outside, and i still have to do the same. if i let it sit, it runs for a few seconds, then dies out. it will do that until i keep it running for about 5mins. it does it with the choke on or off. This can't be normal is it? its all stock, except for a K+N filter, could that be throwing it off? if so i will just switch to a stock air filter.

however, once its warmed up, it runs flawless, and even when i turn it off. it still start right up when warm.

thanks

Jon

[Rico]

Put a 42 pilot jet in the carb. garaunteed fix

[Woodsrider]

Originally posted by Rico
Put a 42 pilot jet in the carb. garaunteed fix

Depending on where you live, after you do this you may never have to use your choke again;) I rarely ever have to use mine now.

[2004exrider]

all 400ex's are very cold blooded. definitely get the #42 pilot, i never use my choke (not even in the winter). when you have it in just pump the throttle 3-4 times and turn it overr it will start right up!

[TheFontMaster]

Yea jet it a little richer for the winter, My 300ex did the same thing.

[awsomeaussies]

Can you still use a 42 pilot jet with a white bros silencer and a k&n filter? Or what would be better?

[JOEX]

Originally posted by awsomeaussies
Can you still use a 42 pilot jet with a white bros silencer and a k&n filter? Or what would be better?
Yes, you can;)

[LI400EX]

can you use the 42 pilot jet, ith the white bros slipon and k&n with airbox lid with holes? I also want to put in a hotcams stage 2 will this all work togehter

[Woodsrider]

Originally posted by LI400EX
can you use the 42 pilot jet, ith the white bros slipon and k&n with airbox lid with holes? I also want to put in a hotcams stage 2 will this all work togehter

Yes Pilot jet is the idle to 1/4 throttle circut of the carb. You'll be fine there, but the main jet and the needle settings will need to be changed.

[LI400EX]

what size do I need tp upgrade the main jet and needles to in the carb if i increase my cam? Good cam to buy also?
I live in NY and ride motocross and gncc

[2004exrider]

if the only mods you have are the k&n and slip on exhaust, then id go with a hotcams stage 1. for the jetting id start out with a
k175, then go on from there with your jetting. it might be a little lean or rich just make sure to check the color of the sparkplug and it will tell you.