Thread: Jetting 101
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Old 13-06-2007
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Keg Keg is offline
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Join Date: Apr 2002
Location: 2 Stroke Town
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ADJUSTING YOUR FUEL SCREW - 4 STROKES

The fuel screw can either richen up or lean out your bike at idle and just above. This setting has a massive performance influence on responsiveness off the bottom and good starting!

There are a couple of easy ways to get your head around adjusting this.

1) REV METHOD
After giving the bike a quick rev to about 1/2 throttle
- If the engine hovers just above idle for a second or two then settles the bike is too lean. Wind the fuel screw out a 1/4 of a turn or more.
- If the engine drops below idle for 1/2 a second and then returns to idle it is too rich. Wind the fuel screw in half a turn to lean it out.

2) CHOKE METHOD
If the bike starts easily on choke on a average temp morning and then can be turned off after 30 seconds the mixture screw is usually pretty well set.
- If the bike needs to stay on idle for a lot longer it is usually too lean (turn the fuel screw out to richen it up)
- If the bike starts without choke it is usually too rich (turn the fuel screw in to lean it off)
If it is a very hot or cold morning then this should not apply. Cold morning will need alot of choke and hot mornings will need very little.
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