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high idle lag on wr 250

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Any help would be appreciated, this is very old.... I have a 02 wr 250 that will produce a high idle lag time, by which I mean, the idle will be very high, till breaking caused the idle to come down, then it will stay there until the throttle is cracked open again. I can adjust this out with the fuel screw,, but the problem will re-occur. I have a JD jet kit and other mod's on the bike. The only time that I've been able to correct the problem was when I was running a continious flow injection system (it goes between the head and carb).. But it's such a tight fit, that the air boot is cramped and squeezed back. Also any carb adjustments are a pain, as the carb is hard bolted into place. I believe that system made it run rich(for reference). As you can imagine, coming into a technical section with the bike in ~1500 rpm idle makes it interesting and fun...

Thank you for any help

Matt

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The source of your hanging idle is likely a lean condition. I'd check the intake tract for air leaks by squirting some starting fluid at all the joints while the bike is idling. If it speeds up, you've found the leak. With all the messing around with the intake tract you describe, this seems pretty likely. Maybe your carb boot is cracked or split open. Doesn't hurt to make sure that the exhaust is mated up to the head properly as well.

You're right in adjusting the fuel screw outwards, but if it comes back, then that sounds kind of fishy. Do you have the spring/washer/o-ring installed properly (in that order) on your fuel screw? Is the o-ring damaged?

If you've got the fuel screw open more than 2-1/2 to 3 turns out from fully seated, you'll want to go up one step on the pilot jet, reset the FS to 1/2 turn and start adjusting from there.

Some have experienced hanging idle due to mis-adjusted intake valves. Have you had trouble starting lately? Have you checked the valve clearances lately?

Just a few thoughts. Hope it gives you some ideas.

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Matt,

In addition to barton's suggestions-

Look for air leaks. Remove the spacer on the airboot screw and clamp to the engine. Tighten the clamp screw further. Check the hot-start for leaks. Try a step bigger pilot jet as described before.

James

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