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Fuel Screw

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I have read several different procedures on how to set the low speed fuel screw. On a Klx300 what is the preferred method for optimal performance ?

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Here's how I do it...whether it's textbook right or wrong, I don't know.

First, the jetting has to be in the ballpark, especially the Pilot jet. Clean air filter. With it at a starting point of about 1.5-2 turns out from GENTLY but fully seated, adjust the idle to the correct rpms (about 1200-1300). Then turn the screw in (leaner) towards the seat until it the idle changes. Note the position of the screw. Now, turn it out (richer) until the idle drops. Set the screw position between these two extremes. Ride and see how it runs.

IF it pops on deceleration, I turn it out a bit more. I've heard some people that keep turning it in until it pops on decel, then, they turn it out least half a turn and re-test. Of course, if your Pilot is too small, it will always pop on decel, or, if you have an exhaust air leak it will always pop on decel.

Hope that helps. Sorry I don't know the manual's direction on it. Maybe at least it helps to know that "in" is leaner, and "out" is richer, if you didn't already know....

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I do just like Blackheart suggests. Also, for my KLX250, if the best idle is with the screw at 1 turn out or less, the pilot jet is too big so get a smaller one. And, if the screw is 3 or more turns out, the pilot jet is too small, get a larger one.

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The first thing you want to do before you start trying to tune it is get an aftermarket mixture screw so that it can be adjusted when the bike is running.

Other than that, the above comments are pretty spot on.

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The first thing you want to do before you start trying to tune it is get an aftermarket mixture screw so that it can be adjusted when the bike is running.

Kouba makes a good one. If you want to make your own tool so you can access the slotted stock screw, that can be done, also.

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Sears makes a pretty good little short screw driver which I have been using since I purchased the bike back in 1999. Have not had any issues with making adjustments to the fuel screw but have read several different methods of doing the adjustments for proper low speed performance from various sources. I appreciate all the input I have received. Now I need to get the carb off the bike, cleaned up, back on, adjusted, and then the most important part----get out and ride.

Thanks again.

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