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07 crf150r idle issues

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07 crf150r, fresh to-pend, head checked valves in spec, shimmed per service manual, low hrs, would not run when I got it. had a132 main, 32 pilot. 140 main now. will not idle consistent. Idles normal when starting once you give it gas the idle hangs like its lean. Have gone up to at least 55 pilot jet seems to run better but still seems to have hanging idle. Best combination for idle 55 pilot jet 3 1/2 turns on the fuel screw. Checked for vacuum leaks, cleaned carb and replaced all jets. Inspected accelerator pump slide and o-ring on fuel screw. Stock needle number 3 position.

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Do you still have a 32 pilot ?

If so it's way too small. My son's 07 has a 40 pilot and 140 main jet and idles perfectly.

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Sounds like you may have a valve clearance or timing issue if you have gone all the way to a 55 pilot (which is way too rich)

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Is your hot start cable stuck or is the hot start 'plunger' not seating properly and allowing air to bypass the carb ??

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Double checked timing, right in the marks. Checked hot start and choke, both seating. Unplugged to no change. I tried 32,35, 40, 42, 48, 50, 52 and 55 pilot. Odd thing seems to only run good 2.5- 3.5 turns out regardless of pilot size. Only difference is smaller pilot engine revs up with choke. Larger pilot it dies. I've had a few fcr carbs apart. Leak is stock.

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Also checked valves. In spec. And blew all circuts out again. Runs great, mid and top. 5500 elevation.

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These bikes all have that issue, fuel screw adjustment is very critical. Let the bike heat up before adjusting. Keep the idle high while adjusting fuel screw and  blip the trottle to see if hanging idle drops. This takes awhile, needs to be adjusted when ever you ride in different elevations.

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These bikes all have that issue, fuel screw adjustment is very critical. Let the bike heat up before adjusting. Keep the idle high while adjusting fuel screw and  blip the trottle to see if hanging idle drops. This takes awhile, needs to be adjusted when ever you ride in different elevations.

 

The 150 R/B is one bike that really likes a flow splitter (like the FMF Snap). It smooths out the bottom end throttle response and just about completely eliminates the sensitivity to fuel screw adjustments.

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Just one more question: When you removed the pilot jet, do you squirt carb cleaner up through the little path in the carb that goes from pilot jet into the carb 'throat'. I always do this followed by blowing compressed air up there afterwards. You should be able to see the carb cleaner being blown out through the carb throat. This passageway is very small amd can easily block, so no amout of adjustment on the fuel screw will get the bike to idle right.

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