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Missouri CRF 250X 04, JD Kit installed, Backfire and Bog off idle

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Installed the JD Kit tonight and cut the 4 1/2 inch by 4 1/2 inch hole in the airbox. Put in the 158 main jet and the red needle with the clip in the fifth position. Went with the fuel/air screw 2 1/4 turns out and have backfire and big time bog off of idle rolling on the throttle. Does not do it every time but most. I am not sure if this is considered a rich or lean situation? Looking for advice on which way to go with the air/fuel screw. Thanks.

malibu3

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First off make sure the bike is good and warm, ride it hard for 15-20 min to make sure every part of the motor is at proper operating temperature. Then start with the screw at the recommended position per JD, start by truning it out in 1/8-1/4 turn incriments and riding it hard for 10-15 min each time to see if it's better or worse. Don't go past 3 turns out. If that doesn't work, then try going in with the needle following the same procedure above. You need to try this first before you try chaning the clip position, neelde or MJ.

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Some VERY good advice on how to approach the running condition. The popping is most likely lean and anything less than a fully warmed motor will be more sensitive.

Keep the idle set slightly high, per the manual's recommendation.

James

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Hey Guys Great Advice! I Have A Simalar Situation I Need Help With. "05" 450x, Jd Kit, 45 Pilot, 170 Main, Air Box Mods, Red Needle 4th Groove, Boyseen Quick Shot, Fmf Mega Bomb Header-titanium Tailpipe(off Of "05" 45r). I Have A Serious Backfire On The Decel. Any Ideas?

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thank you. how big is too big on the pilot? i need to be @ 3-4 turns out for all to work well. i tried a 48 pilot with a 170 main and the problem didnt get much better. should i move the clip as i increase pilot sizes?

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