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Testing Your Main Jet size


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Here's a quick test that will tell you if you have to large (rich) or small (lean) main jet in the carb....
Run the bike through the gears into third gear and run third up to 60-70 MPH full throttle, then chop the throttle about 1/8 to 1/4 back and see if the bike either surges ahead or stumbles then recovers.

If it surges ahead, your jetting is lean and should be increased in size.
If it stumbles and recovers , your jetting is rich and should be reduced in size.
If it makes no difference, you're pretty close.

Quick and easy, pretty accurate too.