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Old 03-03-2018, 02:07 PM
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Default back fire issues

     

I have 2006 YZ 250f. Doesn't want to idle with choke off and is back firing when decelerating. Put new spark plug in and new air filter on. no help with issue. any suggestion?
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Old 03-03-2018, 04:46 PM
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Clogged pilot jet is the most likely cause for the running issue and can cause the popping as well. The other cause for popping is a bad exhaust gasket where the pipe mounts to the head. If it leaks it makes the exhaust real lean and causes the pop.

Paw Paw
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Old 03-05-2018, 09:40 AM
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If you've had the carb apart recently and took the slide out, make sure you didn't install the metal plate on the slide upside down, it looks right when it's not.
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Old 03-09-2018, 05:12 PM
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If you haven't had the carb apart, don't get carb cleaner on the slide plate seal. It will ruin it.
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Old 03-27-2018, 07:32 PM
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I took the carb out had it scrubbed by a mechanic, just put it all back. Still having back fire issues

---------- Post added at 07:32 PM ---------- Previous post was at 07:29 PM ----------

Didn't do exhaust gasket. just because it doesn't pop with choke on. Could it still be exhaust gasket
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Old 03-27-2018, 09:32 PM
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Yes the exhaust pipe gasket can cause this popping if the exhaust has been removed for any reason and then reinstalled with out a new gasket. This causes an air leak in the exhaust which creates a lean condition and thus the popping. A partially clogged pilot jet can do the same thing. Having the choke on makes the fuel mix richer and will reduce the popping as the fuel mix has now become richer.
If the bike will not idle without the choke being on , then it's the pilot jet being dirty.
If the fuel screw is not adjusted properly it too can cause the popping.

Paw Paw
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