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WR250F Jetting

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Hi, I have an 04 WR250 with FMF Q and throttle stop shortened. I bought it used but was told it had been re-jetted to take account of the FMF. It seems to run ok but last night I thought I'd do the grey wire mod anyway(although I'm in the UK this is a US spec bike). I took it out for a quick ride today to see if I could tell any difference and although I don't think I could when I got back the exhaust was quite black so it looks like it's running rich. If the bike had been jetted for the FMF with grey wire attached would removing the wire cause it to run richer?

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I don't expect removing the gray wire will make much of a difference in jetting, at least not to be noticed at the tailpipe.

James

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Ok thanks. As I only went for a short 30mins ride on the road mainly at mid throttle (for a guess) where do you think I should start looking for the source of richness?

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What are the fuel screw setting and needle clip position?

It would help to know the pilot jet size (#42?) and needle code (OBExx or OBDxx).

The needle clip position may need to be leaned and/or fuel screw turned inwards to get the bike running cleaner.

There are also other things to consider. My '04CRF250R was smoking excessively and the jetting was not rich. The motor, instead, was burning oil from a bad valve seal. In this case, it was using motor oil consistently on every ride.

Try a few carburetor settings staying within a reasonable range from stock and the bike should perform well and run clean.

James

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Thanks for that James. I suspected you may want that sort of info but never having been inside a carb before I'll need to pluck up the courage first.....

I hope it's not a valve problem as the bike is only 3 months old with 250 miles on it :cry:

I will have a look at the things you mention though

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