400ex starting problems

[400exboy2]

hey guys i have a stock 2006 400ex and since i had it i had alot of starting problems with it. ive gone though about 7 or 8 plugs in the last 4 months with it. i got it in the summer and had an ok time starting it and now that its getting a little cooler outside and winter is coming for us its hard to start. i turn the choke on do not pump the gas or anything and it starts right up on full choke but then when i take it off full choke and put it on half choke it starts running rough and it will only idle every time. i go to give just a little bit of gas on it, and it stalls out and most of the time it will just keep starting up but cut off after a couple of seconds everytime to it gets to the point where it wont start at all and when i take the plug out its black and has i guess gas on it. the only way i can start it without it fouling a plug is to start it on full choke let it run for a couple a seconds then put it on half choke and let it run for about 3 minutes (if it will) then turn the choke off and i can give gas and it runs like a champ its doesnt bog down or stall at all. my friend told me i should try a 42 piolet jet on it would it help it start better? i just want to get it running right for the winter time and not have to worry about it fouling plugs on me. well any help would be greatly appricated thanks Kyle

[Live2Ride300]

Is the engine all stock?

[TravEX]

You can do a search, there are a 100 threads on this, but I'll try to help.

The 42 pilot will help. The best way I've done in cold weather is full choke and about 8-10 QUICK pumps of the throttle, hit the starter without the throttle, and AS SOON AS it starts fast idle it with the throttle and cut the choke to half. If you run it long at all full choke, you'll foul a plug. In the cold winter I run 2 plugs all winter, I swap them out each time I ride. It seems, on mine, that the plug that is in the motor doesn't want to start it good, but the other one will. Sounds like a headache, but it's easier than running the battery almost down then changing the plug.

The cold starting (most will agree) is the ONLY problem with the 400EX. Once you get it started that first time for the day it's fine.

Practice and time are the best way to figure it out.

Travis

[John Pennella]

My buddy has an 05, and I they all take a long time to warm up to the point that it'll run with out the choke. He'll fire it up and have to ride for almost 4 or 5 minutes, even after letting it warm up, on the choke or else it'll stall. After it's really warm, it runs like a champ but the thing doesn't want to run unti it's fully warmed up. It's stuborn. But this quad is stock so i don't if your is but he's having the same issue like you. It's probably just the stock jets causing the problem.

[vze2hnvz]

Just in case you don't know your way around this carb - ;)

http://www.atvriders.com/articles/pilotjet.html