jetting

[exrider49]

i am having hard time gettin my quad running better..its a 400ex with pro design pro flow kit with billet insert, stock airbox with lid on, for exhuast i have fmf powerbomb headpipe with hmf slip-on..i just recently jetted it with a dynojet stage 2..170 main, fuel mixture screw 3.5 turns out...it starts up and idles smooth but when it warms up and i go to rev it up, it cuts out then revs..it just like misses when i crack the throttle hard but when i dont hit the throttle so hard it will rev up how it is suppose to...please help im new to jetting and workin on carbs.

[CarGuy7a]

try setting the mixture screw at 3 turns out. i sort of had the same problem.

if that doesn't fix it. try taking the air box lid off for a quick diagnosis of the problem. if it runs better with it off, it's rich.
if the problem get worse (loud popping sound at full throttle) then it's too lean.

[exrider49]

allrite im gonn aplay around with it and see what happens thanks for the help

[Eviltanker]

You sound rich. lower the main , needle in the middle, What size is your pilot jet?also try 2 1/2 turns on the screw, That will get you started. This is just a good start point. from there buy a few plugs and start doing plug chops.

[exrider49]

i figured it out guys thanks for the help!!