Home. Back. ...... The Gas Gas Guru. Technical Information.
Dear Jon,

I have a 2001 Gas Gas 321. I am having difficultly with jetting. My riding area altitude is 3750 feet, dry, and this time of year, cool. I am currently running a 114 main jet - gas/oil mixture @ 80:1 w/unleaded 100 octane. The engine response off bottom is not as crisp as I'd like it. I've tried various positions for the needle and coresponding adjustments of the fuel screw, but still have not been able to get the response off bottom that I'd like. What main jet and needle setting would you recomend?

Thank you


My first guess is that the pilot jet may be too lean. It may be a 30 and should be changed to about a 36. The main sounds about right at 114 or 116 in some cases. Try the needle in the middle clip and the air screw out to 3 1/2 to 4 turns to start with. Let me know how it's going.


Dear Jon,

I have got the 321 jetted pretty close now 112 main modified pilot to ~ #40
needle 2nd position from top Fuel screw - I am still fine tuning.

Professional tuner and 'Trials Competition' writer Jon Stoodley has very kindly stepped up to the plate to answer your questions. If you're having problems, or need some advice just send an email to Jon. If it's something that could be useful to others, we'll post it on the site.
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