Backfiring
Thread Starter
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Novice
Joined: Sep 2010
Posts: 22
Likes: 1
From: St Petersburg, FL
Backfiring
Hey friends - I have a '97 Heritage. It has started backfiring a bit as it is running especially when cold about every 10 seconds...I'm in FL so it's not really cold. Going down the highway is fine but backfires a lot when backing off throttle. I checked fuel filter = it's fine, plugs look fine maybe a bit lean.
Any ideas?
thx
Any ideas?
thx
Thread Starter
|
Novice
Joined: Sep 2010
Posts: 22
Likes: 1
From: St Petersburg, FL
Thanks I'll give that a try. Yes aftermarket exhaust. This just started though.
Stellar HDF Member
Joined: Mar 2006
Posts: 2,395
Likes: 153
From: Utah
Something is making your bike run leaner... my guess would be clogged jets or a vacuum leak. At least, that's where I would look first. Vacuum leak is easiest to test... spray water around hoses, intake manifold, and carb. If the idle rises, you have a leak.
Try seafoam in your gas... half a can per tank for the next few tanks.
Try seafoam in your gas... half a can per tank for the next few tanks.
Road Master
Joined: Feb 2011
Posts: 784
Likes: 10
From: SE Pennsylvania
The bike isn't running lean. It's backfiring because the air coming in through the back of the exhaust is burning the un-burnt fuel up near the header pipes. You may need to reduce the enrichment a tad. It's a compromise....a bit of backfiring on deceleration, or a slightly lean running engine where all of the fuel is burnt before the exhaust. A slightly smaller diameter baffle will also help.
Thread Starter
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Novice
Joined: Sep 2010
Posts: 22
Likes: 1
From: St Petersburg, FL
Vacuum line
The vacuum line is connected to the carb but loose on the other end when I took it off. Where does this connect to?
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Thread Starter
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Novice
Joined: Sep 2010
Posts: 22
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From: St Petersburg, FL
Thanks!
It's funny I was looking at your Converse shoes and that is what I was wearing Friday....and I'm 65! = refuse to grow up!
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Stellar HDF Member
Joined: Mar 2006
Posts: 2,395
Likes: 153
From: Utah
That screw didn't move until you adjusted it and if, as you say, there were no changes (including you didn't move to a lower elevation) you are simply covering up the real cause. It may show up later again. If the vacuum hose was 'loose' that would be a good place to start.
C#
C#
Thread Starter
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Novice
Joined: Sep 2010
Posts: 22
Likes: 1
From: St Petersburg, FL
That screw didn't move until you adjusted it and if, as you say, there were no changes (including you didn't move to a lower elevation) you are simply covering up the real cause. It may show up later again. If the vacuum hose was 'loose' that would be a good place to start.
C#
C#
On the way to work this AM I noticed that there was gas coming out of the overflow hose on the bottom of carb. Could it be I dislodged a bit of grid that is interfering with the float needle?