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2004 KTM 450EXC Jetting

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Need some help/advise....I have KTM 450 EXC that pops, barks and backfires when rpm's are decreasing. Elevation in Pgh Pa is 750 feet. I was told to change the pilot jet from stock (to a #50)by the KTM dealer. The change did not produce any results. I suspect I could do better than this with some good advise.

Need recommendation to fix up the stock(or slightly modified) jetting!!!

thanks Kookey1 <font color="orange"> <font color="orange"> :thumbsup:

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There is a possibility that the jetting is too lean, or the headpipe is leaking off the cylinder. Try turning the fuel screw outwards and use a richer clip position. If there is still no improvement, one of the exhaust flanges is probably misaligned at the weld. Try sealing the flange with hi-temp sealer to check.

The pilot jet should not need to be a #50, considering a #42 is stock, which is 3 steps richer(42-45-48-50). If you have any difficulty starting the bike when hot, the pilot jet and/or fuel screw is too rich. Turn the fuel screw inwards to lean the jetting until starting improves.

The bottom line here- You should not have to compromise starting to reduce popping on deceleration. If the popping is is loud and persists, look carefully at the headpipe.

The jetting kits had little to no popping on deceleration in most cases (see banner add kits above at top).

James

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