starting trouble

[400exdave]

Ok. I'm getting irritated here, so I thought I would ask the experts on what to do :D

Alright, I put the choke on full and hold the start button and it starts, and while im holding the throttle aprox. 1/4 of the way the bike is revving and sounds good.... then all of a sudden it starts sputtering, so I turn it down to half choke... and it revs fine with me holding the throttle, then it starts sputtering again and sounds like its gonna stall, so i move it to no choke and its running good then all of a sudden just stalls out. so i try starting it again and it wont start at all, I have to have a battery charger hooked up to it while im starting it so it wont kill the battery. and it still doesn't start. I'm running a 155 dyno jet main, and a stock pilot jet and a needle on the third notch. I'm running a 155 because that is what i was told was a good size. now is a dyno 155 bigger(or smaller) than a 155 kehein jet size? any help would be good. I am within 300 feet below sea level. I have a k and N filter with lid off, and a full yoshi pipe on there. this is really bugging me and i need help!!!

thanks

dave

[jonc623]

do a plug check and see how it looks if black too rich if light brown about right white or real light tan too lean i think you are running rich but hard to tell with out looking

[Joe400ex]

check and see if the gas is old plus what kinda gas are u running in there:(

[400exdave]

im running 90 octane gas. yeah, my plug was black on the tip of it. so the next size down jet size i have is a 146, i guess ill try that then. thanks