Thread: carb tuning
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Old 01-06-2009, 01:01 PM
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jasonh jasonh is offline
Motorized Bicycle Elite Member
Join Date: Jun 2008
Location: Longmont, CO
Posts: 1,590
Default Re: carb tuning

You only have a couple adjustments you can make really: the idle speed screw and the needle for the main jet.

If you take apart the slide there is a long needle. This has a clip on the end of it. Stock position should be 2nd from the top. leave it there at first. Once you get the bike running you can set your idle speed to whatever you want it at. Ride the bike a few miles then shut down the motor and let it cool. Pull your spark plug and look at the tip. It should be a darkish tan color, maybe even the color of milk chocolate. If it's black and oily, you're running rich, if it's light colored or white, you're running lean.

If you're running rich, pull out the needle and move the clip up one notch. if you're running lean, move the clip down one notch. Clean the plug and test again.
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