Why all of a sudden am I getting a backfire?


Information and questions on GL1200 Goldwings (1984-1987)
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Senkoguy1
Posts: 27
Joined: Fri Apr 26, 2013 8:18 am
Location: Red Hook NY
Motorcycle: 1986 GL1200A

Why all of a sudden am I getting a backfire?

Postby Senkoguy1 » Tue Jul 02, 2013 7:07 pm



Recently I started getting a backfire out of my left side exhaust. It's not loud, but it's not normal. Any suggestions? I'm not afraid to put a wrench to my bike. 76000 miles.



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virgilmobile
Posts: 7663
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Location: Denham Springs,La.
Motorcycle: 1988 GL1500 I
Previously owned
78 GL1000
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84 GL 1200 I

Re: Why all of a sudden am I getting a backfire?

Postby virgilmobile » Wed Jul 03, 2013 8:30 am

Backfire from the exhaust is exploding unburnt vapors accumilating in the exhaust....

I'd pull the plugs on that side and see how the cylinders are firing....One should be rich and sooty.
Also,from cold,let it idle only for 5 seconds...lightly tap the headers...all 4 should be the same temp.
The engine could be misfiring from anything from carb issues,ignition wire/cap age,fouled spark plug,stuck air cutoff valve,poor compression,etc...So do the easy stuff first...
Plugs,caps and wires...Test the ignition timing(both mechanical and the vacuum part)compression test,then carb sync or repairs as needed.

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Blue&Gold
Posts: 8
Joined: Sun Mar 24, 2013 3:38 pm
Location: Healdsburg, California
Motorcycle: 1987 GL1200 Interstate

Re: Why all of a sudden am I getting a backfire?

Postby Blue&Gold » Sun Jul 07, 2013 10:12 am

I get a backfire occaionally on my '87 interstate (105K mi) if the idle is higher than 1.5K and I kill the ignition from the key or kill switch.

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Mooseman
Posts: 383
Joined: Thu Sep 10, 2009 11:10 am
Location: Napa, CA
Motorcycle: 1996 GL1500SE 88k
1986 GL1200A (SOLD) 81K
1985 GL1200A (SOLD) 85K
1986 BMW K75c 25K

Re: Why all of a sudden am I getting a backfire?

Postby Mooseman » Mon Jul 08, 2013 11:45 pm

If the carbs get out of sync, it can cause a backfire.
Enjoy the ride. They are all good, just some better than others.
Mooseman

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Senkoguy1
Posts: 27
Joined: Fri Apr 26, 2013 8:18 am
Location: Red Hook NY
Motorcycle: 1986 GL1200A

Re: Why all of a sudden am I getting a backfire?

Postby Senkoguy1 » Tue Jul 09, 2013 12:38 pm

Found out carbs were synced on a bench just before I bought it so I'm going to have it done right after our season. Local Honda says they can't look at it for 3 weeks, which I kinda understand.

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Mooseman
Posts: 383
Joined: Thu Sep 10, 2009 11:10 am
Location: Napa, CA
Motorcycle: 1996 GL1500SE 88k
1986 GL1200A (SOLD) 81K
1985 GL1200A (SOLD) 85K
1986 BMW K75c 25K

Re: Why all of a sudden am I getting a backfire?

Postby Mooseman » Tue Jul 09, 2013 5:25 pm

I'm not sure how good a bench sync is vs on the bike running sync. I just know that the times mine has backfired, that was my problem. When I got it right, it no longer backfired.


Enjoy the ride. They are all good, just some better than others.
Mooseman


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