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greg_gorrell
06-10-2005, 01:30 PM
does anyone know the stock jetting in a 400ex...i have a white brothers pipe im putting on to where im gonna need to put in a 150 main and a 40 pilot. It is running pretty hot right now since summer has came but i would like it to start a little better then it is. I know to start easier i would need to put in a 42 pilot but i dont want to screw up the jetting for my exhaust. does anyopne have any reccomendations, i know its gonna be hard to explain not knowing my elevation or any of the other factors but i do have the stock airbox/filter at the moment.
RiderTRX400ex
06-10-2005, 02:09 PM
the pilot jet shouldnt affect your main jet, the pilot is only up to 1/8 throttle...
RiderTRX400ex
06-10-2005, 03:16 PM
and stock jetting is a 38 pilot and a 146 or 8 ? main
2001400exrider
06-10-2005, 08:44 PM
stock jetting,

main- 148
pilot- 38
greg_gorrell
06-10-2005, 09:48 PM
i know how the jets work but what i mean is like when you remove the choke on a stoke 400 you are going from a 38 pilot to a 42. for my pipe i need to put in a 40, is it going to make it start easier if put in a 42 pilot instead of the 40 and will it throw off the jetting for my exhaust and make it run richer than it should? i have really never messed with the jetting and i know this is going to be a frustrating task since they dont know my elevation or anything and im probably going to have to tear the carb apart a few times. im just trying to get this **** figured out so i can get it done as quick as possible. if it helps im running it in anywhere from 50-90 degrees and im riding at an elevation of around 2,100-2,300 feet with no other mods that would affect the jetting.
greg_gorrell
06-11-2005, 10:11 PM
no one can help me out?
insaneracin2003
06-11-2005, 10:58 PM
i never changed my pilot jet ever,i used to run an HMF slip-on with stock pilot and a 155 main,2 1/2 turns out on the air screw and it ran like a bat out of he**.i also ran a UNI filter.I dont think anyone is neglecting on helping you but one of the best features here on atvriders.com is the search option at the bottom....just my 2 cents.
400exrider707
06-12-2005, 08:22 AM
Try a 40 pilot and 152 main and see what the plug looks like from there.