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Backfiring on Deceleration

Old 01-08-2014, 09:54 AM
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Backfiring on Deceleration

Hi - I recently rejetted with #48 pilot jets. The bike runs incredibly well now and has for several hundred miles. However, when coming off hard acceleration it backfires and pops quite loudly. I understand this is the result of a lean mixture.

Am I doing any long term damage? Damaging valves, etc? I love my new performance but I don't want to hurt my hawk.

Does anyone have any insight?

Thanks,
Steve
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Old 01-08-2014, 10:07 AM
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Old 01-08-2014, 11:22 AM
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Originally Posted by ChillyWaa View Post
Hi - I recently rejetted with #48 pilot jets. The bike runs incredibly well now and has for several hundred miles. However, when coming off hard acceleration it backfires and pops quite loudly. I understand this is the result of a lean mixture.

Am I doing any long term damage? Damaging valves, etc? I love my new performance but I don't want to hurt my hawk.

Does anyone have any insight?

Thanks,
Steve

That is a great forum to read through, also just a side note. Check all of your exhaust gaskets.

My bike just recently started popping real bad on decel and I couldnt figure out what the cause was, turned out the exhaust gasket from the rear header to mid pipe had just enough of a leak to let fresh air into the pipe and cause it to pop on decel. I didnt find it till one day I got on her really hard and then lost all power and slowed down and could hear the exhaust leak.

Now that I have replaced the gasket, no more popping.

Last edited by sailorjerry; 01-08-2014 at 11:25 AM.
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Old 01-08-2014, 12:40 PM
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That's not a problem... that's a FEATURE!

Personally I love the occasional popping on decel. I think it's a cool sound that makes my bike noticeably different!
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Old 01-08-2014, 01:30 PM
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I love that sound to it scares women and children
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Old 01-08-2014, 06:07 PM
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If you've gone up in jetting its most likely an exhaust leak.
Usually from the graphite gaskets or even a pin hole in the header pipes.
Whatever it is its letting in oxygen into the hot exhaust mix. If the leak is after the valves it's not doing any damage.
If you've had the PAIRS (or whatever honda calls theirs) system blocked off that could be leaking.
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Old 01-09-2014, 08:39 AM
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I agree, I like the noise.

But since I was tinkering with the carbs, it sounds like I screwed up the PAIR install.

Even though I went up to #48s - is it possible to run lean now by incorrectly correcting a vacuum line or something?

I'll check the front plug tonight and confirm. Thanks for all of your help even if there is some debate in past threads I read.
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