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XR650L with FCR mx - Rough idle.

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2008 650L with the FCR mx swapped in. Runs terrific in all throttle settings except the idle is a mess. Wont idle cold without the choke on. Small back fire then dies. Idel RPM varies all over the place. Takes a long time for the bike to be warm wee its stable.

I have the adjustable fuel screw. Main 165. Main Air jet - 200. DTP needle. 35 pilot.

Run in Portland Or.

Any help / comments would be appreciated.....

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Your symptom indicates a pilot circuit issue. That pilot sounds very small, but I don't know for sure on the conversion.

Most FCR's use a 42-78 pilot.

I would replace the pilot jet with a fresh one, check the fuel screw for a fresh oring, and start again.

The passage above the pilot gets clogged very easily, so you might want to push some monofiliment up there to make sure it's clear. It's an 's' shaped passage.

If the idle is set too high (stop screw) and the fuel screw is set out of adjustment to compensate, you will have the same problem.

Start with 1.5 turns out on the fuel screw, then set the idle, then adjust the fuel screw for max idle, then drop the idle again to normal idle rpm.

Edited by Krannie

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