View Full Version : idle and jetting confusion
a7x_84
06-09-2009, 10:59 PM
ok i put a 150 jet in my quad, it ran great through all positions of throttle but then it had no throttle at all. the spring for the idle screw broke so i am adjusting it with a damn needle nose and dont know how many rotations i am going. can someone tell me a good setting for the idle screw and a would a 150 jet be better than a 140 jet...
no airbox lid, uni foam filter, white bros rev box, and stage 2 hotcam..
any help is appreciated
GPracer2500
06-09-2009, 11:58 PM
You don't count rotations for the idle adjustment screw. Just turn it in until the engine idles. It's really just a throttle stop screw that keeps the slide/butterfly cracked open ever so slightly.
The fuel screw is the adjustment where you lightly seat it and then back it out a certain number of turns (usually 1 to 3 turns out). The fuel screw is part of the pilot circuit. It fine tunes the pilot jet.
And the stock main is a 148. So don't put in a 140 (I'm assuming you're using Keihin jets and not Dynojet jets).
a7x_84
06-10-2009, 06:41 PM
no actually im using dyno jets, is there a big difference
GPracer2500
06-10-2009, 07:13 PM
They use a different scale. You can always trail-and-error to find the best settings. Just make one change at a time.
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