Sudden onset backfiring

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Oct 29, 2010 | 12:08 PM

lfmn16

Thread Starter

Tourer

Joined: May 2010

Posts: 287

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From: charles town, wv

Sudden onset backfiring

2007 Softail, stage one, Vance and Hines Pipes, Spike air filter (can't remember who makes it, but it wasn't one of the cheap ones) 11,000 trouble free miles with all scheduled maintenance done at a dealer that I trust. Last mod was done about 1,000 miles ago - replace K&N air filter with the spike. I specifically asked if it needed to be remapped or dyno'd because of the replacement and they said no.

I went for about 150 mile ride last Sunday. About 120 miles into it I started to get backfire on deceleration (It's never happened before). It got worse and at about 145 miles the bike stalled at a stoplight. It started right back up and the last 5 miles home I had no more problems. I put gas in as I started the ride - high test at a station where I have stopped before. It was a sunny day and a route I ride often.

Any ideas? I'm going to take it out this afternoon to see if I have any problems.

Thanks.

Last edited by lfmn16; Oct 29, 2010 at 12:11 PM.

Oct 29, 2010 | 05:42 PM

Old Gunny

Road Warrior

Joined: Nov 2007

Posts: 1,984

Likes: 7

Trying to think what might cause this. Gas at first, but then no, you covered that.

Maybe the IAC stuck closed. This is something that could happen anytime, cause it happenes sometime.

I think this would cause a rich condition, slowing down, (zero throddle backfire) and even stall you out when stopped or at idle.
And something that could go back to working.

Clean it out, use carb cleaner not brake cleaner. I like to spray some silicone spray into the inlet hole when running to give it some lubrication.

Brake cleaner run thru the combustiuon process exhausts Phosegene gas I read in AIM I believe it was. Seriousely ruin your day, at the least.

Oct 29, 2010 | 06:58 PM

asm481

Road Master

Joined: Aug 2008

Posts: 1,018

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From: Southeastern Wisconsin

I'd be lookin' for something loose. Start with exhaust.

Oct 29, 2010 | 07:15 PM

peppi

Road Captain

Joined: Nov 2005

Posts: 720

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Aside from any engine problems in mapping, I would be looking for an exhaust leak that is allowing air into the system which would cause your problem on deceleration. Check the nuts for torque on the pipe flanges on the head pipes.