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View Full Version : Cold start prob with new 400EX


MikeL250X
12-12-2001, 07:47 AM
Hey guys, I did a search and found a couple responses that the 400ex is hard to start when it's cold out, that its running too lean. I tried to feel for the air fuel screw under tha carb, but seem to find one, I guess I need a screw driver for that, does anyone have a pic of the bottom of the carb so I adjust the right screw. They said 1/2 - 1 turn out, is that enough? it's damn cold here and the quad is brand new, it took over 5 mins to get it to idle last night. thanks for the help guys

in 400EX envy
oynot400
12-12-2001, 08:15 AM
Sorry I don't have a pic, but it would be a good investment to get the shop manual for it. I know some people have rejetted to help with the cold starting problem. I never could get it to go in the cold unless I had it sit in the garage for an hour or so. I ended up getting a different carb. So far that has worked but it has not got real cold yet.
knighttime
12-12-2001, 08:40 AM
The 42 pilot jet solved it. Now I dont even use the choke.
12-12-2001, 09:04 AM
or a 40 pilot..:D
papaw
12-12-2001, 02:40 PM
i run a 45 pilot and don't have a choke.there was a cold snap back in oct. and had to pull start the bike though.i might try my factory rev limiter though. i here it helps in cold starts.right rico.......
hippy440
12-12-2001, 04:34 PM
yes use a 42 jet and keep the stock revbox.
01ytrx400ex
12-13-2001, 06:56 AM
I had the same problem with mine...After I re-jetted it starts right up when cold.
MikeL250X
12-13-2001, 07:21 AM
ok so 2 votes for a 42, one for a 40, and a 45 :D I assume higher number is a larger jet, the quad is going to stay mostly stock for now, maybe a filter and pipe, I think I'll try the 42 for him.
knighttime
12-13-2001, 07:32 AM
That screw you were talking about in your first post should be 2 1/4 turns out from the seated position. When you tighten or seat the screw, just let it seat lightly, or it will cause damage.
papaw
12-13-2001, 03:16 PM
yep the higher the number the bigger the jet,and don't worry about the 45 pilot if your stock.i have oversized intake valves....
12-14-2001, 09:10 AM
Originally posted by papaw
i run a 45 pilot and don't have a choke.there was a cold snap back in oct. and had to pull start the bike though.i might try my factory rev limiter though. i here it helps in cold starts.right rico.......

YUUUUUP.....leave that stocker in there...:D
stevengates45
12-14-2001, 05:36 PM
I have found all EX's to be cold natured. I havent riddin my bike in a while since the racin season ended. Its sortof chilly here. Today I went back to crank it up & it wouldnt even hit so I got my neighbors bear tracker & pulled it off, but as soon as i dropped it in gear it fired right up.