Backfiring in carb
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Intermediate
Joined: May 2006
Posts: 36
Likes: 0
From: Bucks County Pa.
Backfiring in carb
Posting for a friend. He has a 1997 Electrica Glide with only 7200 miles on it . I changed all the fluids & plugs . Front plug was fine white ash in color ,rear plug was jet black .Bike has been sitting for over 8 years .
The two problems I am in countering are the bike is backfiring through the carb as soon as you close the choke . Second is the fuel gage is showing empty when full.
Any help would be great !
THANKS IN ADVANCE .
The two problems I am in countering are the bike is backfiring through the carb as soon as you close the choke . Second is the fuel gage is showing empty when full.
Any help would be great !
THANKS IN ADVANCE .
Seasoned HDF Member
Joined: Dec 2010
Posts: 7,736
Likes: 1,524
From: Coromandel Peninsula New Zealand
Fuel gauge probably stuffed or wired backwards, carby farts are usually caused by the low speed jet being clogged or the wrong size. If there is anything smaller than a 48 I would go up a size or two but if that don't fix it then the inlet manifold gaskets are probably rotten.
Road Warrior
Joined: Nov 2008
Posts: 1,595
Likes: 8
From: Vancouver Island British Colombia Canada
The passages in your carb are plugged with old gas gum & altering your fuel air mixture. you can attempt to scrub your system with a full can of sea foam or you pull your carb off & clean it.
You should also pull your intake off & replace the 2 gaskets. You might have a vacuum leak there!
Look for a ground wire off for your fuel guage. Located near your filler cap if you have a dash on the tank.
You should also pull your intake off & replace the 2 gaskets. You might have a vacuum leak there!
Look for a ground wire off for your fuel guage. Located near your filler cap if you have a dash on the tank.
Outstanding HDF Member
Joined: Oct 2010
Posts: 2,706
Likes: 14
From: Near Frankenmuth, MI
STOP! You have an intake leak when one cylinder is running lean and one is rich. The two seals on the intake, one to each cylinder is a common air leak point and causes just the situation you explained!
Everyone wants to rip carbs apart as soon as a bike doesn't run right. You can mess up a carb in a blink and have to have a pro reassemble it to get it back together right.
Read here (use the search tools or google your issue). There's a few hundred conversations already in the archives that you can get more details from.
Everyone wants to rip carbs apart as soon as a bike doesn't run right. You can mess up a carb in a blink and have to have a pro reassemble it to get it back together right.
Read here (use the search tools or google your issue). There's a few hundred conversations already in the archives that you can get more details from.
Road Warrior
Joined: Mar 2009
Posts: 1,885
Likes: 0
From: Chicago area
I'll give JonnyC a voice and wait. Mine needed a full rebuild. Not vacuum related. Did you compression test?
I have the (dreaded) old butterfly carb!
I have the (dreaded) old butterfly carb!
Last edited by oppirs; Oct 23, 2011 at 05:57 PM.
Seasoned HDF Member
Joined: Jan 2011
Posts: 157,325
Likes: 56,887
From: Michigan 15 Minutes East Of Hell
+1 .... Yep .... Sounds likes an intake leak could be your problem ... check it with a shot of carb cleaner sprayed at / near the connections to the cylinder head and / or boots ... if it increases the idle speed ... BINGO ! you just found your problem ... try and avoid the spray reaching the carb intake as this will give a "false reading". Good luck
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Stellar HDF Member
Joined: May 2009
Posts: 2,856
Likes: 127
From: Middle of Kansas
Just my 2 cents, but it could be a sticking intake valve. That is the only thing I can think of that would cause backfiring through the carb. I would not think an air leak would cause that. I would dump about 4 ounces of Marvel Mystery oil in the gas tank, and run it for a while.
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Seasoned HDF Member
Joined: Dec 2010
Posts: 7,736
Likes: 1,524
From: Coromandel Peninsula New Zealand
Just my 2 cents, but it could be a sticking intake valve. That is the only thing I can think of that would cause backfiring through the carb. I would not think an air leak would cause that. I would dump about 4 ounces of Marvel Mystery oil in the gas tank, and run it for a while.
Stellar HDF Member
Joined: May 2009
Posts: 2,856
Likes: 127
From: Middle of Kansas
Yeah Spanners; That makes sense. That may also be why the rear cyl. is running rich. It might be getting some of the fuel charge that would normally go to the front cyl. Does that sound right?