is there a problem with my fuel system?

[dirtdawg]

i'm jetting my 300ex with a 400ex carb and i can't jet it without having a problem with full throttle. if it sits at idle for like a couple minutes it's fine and also at like half throttle. but, when you punch it off of idle it just dies and shuts off. i started at a 168 main, which was too lean as there was popping back through the carb and it was excessively hot and now i am at a 195 main . i'm 4 turns out on the fuel screw and i was at 3.5 is my float height incorrect or something? should i get a carb rebuild kit? what about the breather hoses on the carb? i'm under 90 feet of elevation with a relatively beat-up k&n, cobra header, and white bros. muffler and 40 pilot.

[Tommy Warren]

what about your pilot jet? you might wanna try going a bit larger..

[dirtdawg]

maybe i should get a new plug or something. the pilot jet is for starting and stuff and that is good. after half throttle, it bogs out and shuts off. if you go slow, it lets you get to the high rpms. but if you hold the throttle at one place for a few seconds, it skips and runs like crap and wants to shut off. ever since i had the quad, if you put the airbox lid on, it acts as a rev limiter. you can't go up in the rpm range with the lid on. maybe that means i'm too rich to have the lid on. i'll try it with the lid on and jet it for that and see if the problems go away.

[Tommy Warren]

there is something wrong with your jetting it doesn't sound right at all.. on a 300ex carb with a pipe and filter you should be at about 40 pilot and 128 main. and your running a 40 pilot and 195 main? that sounds way too huge. you need a smaller main and a largers pilot because at half throttle your carb stops taking fuel from your pilot and starts taking it from the main. so at half throttle your just dumping all this fuel into the motor and thats why you can't run with the airbox lid on.

[dirtdawg]

i have a 400ex carb. i just took it all apart to clean it and now the needle valve doesn't freely move. i took it back apart to check it out and i ended up cracking the part where the post holds the float on. i'm gonna get another carb that is much better than the one i had. the one i got was pretty much **** anyway. this one is much cleaner and was said to be good running. the choke was also taken off of the other one.

[Tommy Warren]

good idea;)