440ex carb jet settings

[mojoe2878]

i have a 400ex with a 11:1 440 big bore kit,w/b exhaust, k&n filter and a stage 1 cam. does anybody know about what the jetting on the carb should be for this quad and whether i need to replace the needle when i go up in jet sizes or can i use the stock needle with the increased main jet. i usually run it with air box lid off and i live in Louisiana so im right at or a little below sea level.also would i need to increase the slow jet any? the quad seems like its heating up to fast and a lean fuel mixture is the only problem i can find, all the jettings on the carb are still stock. :confused:

[cals400ex]

you need to rejet asap!!!



i would try this setup:

160-165 keihin mainjet
stock needle with clip moved down one position
45 pilot jet
2.75 turns out from lightly seated on the fuel screw

[ghak99]

Originally posted by mojoe2878
i have a 400ex with a 11:1 440 big bore kit,w/b exhaust, k&n filter and a stage 1 cam. does anybody know about what the jetting on the carb should be for this quad and whether i need to replace the needle when i go up in jet sizes or can i use the stock needle with the increased main jet. i usually run it with air box lid off and i live in Louisiana so im right at or a little below sea level.also would i need to increase the slow jet any? the quad seems like its heating up to fast and a lean fuel mixture is the only problem i can find, all the jettings on the carb are still stock. :confused:

Just curious, but how long have you been riding it with this current set up?

[cals400ex]

Originally posted by ghak99
Just curious, but how long have you been riding it with this current set up?


i was wondering the same.

[mojoe2878]

ive ridin it about 30 minutes all together since i did all the work on it. afraid to ride it anymore until i get the jetting straight. the quad actually cranks up and runs good. havent gone past half throttle be cause i havent broke it in yet. it heats up real fast but hasnt overheated yet( i dont think it has anyway). i dont know what the normal running temp is for it, planning on getting some temp strips so i can monitor the engine temp. have them on my yz250f and they seem to work well. hopefully i havent done any damage to it running it the 30 minutes that i have, it still sounded good yesterday when i shut it off so maybe no damage has occured so far. only thing i did to the carb when i put it back together was move the needle clip alway down to the richest slot, maybe that helped it out enough to keep it from blowen up on me in the short time that i rode it. also ran 100 octane gas in it with the 11:1 piston i guess thats enough for it, my yz250f has a 12.5:1 ratio and 100 octane is the minimum that can be ran in it so i figured i would be safe with it in this 11:1 quad.