carb explotion, backfire and running on one piston when going slow
Thread Starter
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Road Master
Joined: Jul 2009
Posts: 849
Likes: 13
From: Santo Domingo, Dominican Republic
No particular smoke out of the exhaust when its not shooting flames on the big explosions backfires!
Also, my mechanic did a compression and lean down test and took everything apart and back together with Cometic gaskets and the problem is just like before he did all of that
Also, my mechanic did a compression and lean down test and took everything apart and back together with Cometic gaskets and the problem is just like before he did all of that
Road Warrior
Joined: Mar 2009
Posts: 1,885
Likes: 0
From: Chicago area
No particular smoke out of the exhaust when its not shooting flames on the big explosions backfires!
Also, my mechanic did a compression and lean down test and took everything apart and back together with Cometic gaskets and the problem is just like before he did all of that
Also, my mechanic did a compression and lean down test and took everything apart and back together with Cometic gaskets and the problem is just like before he did all of that
Last edited by oppirs; Jan 7, 2012 at 05:34 PM.
Elite HDF Member
Joined: Sep 2007
Posts: 4,468
Likes: 12
From: Bluffton, South Carolina
Bad intake seals, lifter going bad, perhaps one plug wire was loose and changing them straightened out the problem. You stated going back to points fixed the problem, so maybe the module was bad.
If your indy did a compression and leak down test, then tore your engine down then just replaced the gaskets and that didn't fix the problem, you might want to look for a new mechanic as your engine probably need that. Could you plese put in one post what you did and what where the results of each??
If your indy did a compression and leak down test, then tore your engine down then just replaced the gaskets and that didn't fix the problem, you might want to look for a new mechanic as your engine probably need that. Could you plese put in one post what you did and what where the results of each??
Plugged Pilot Jet.
As soon as you open the throttle the carb transitions more to the main jet and jet needle/tube.
Happens on sleds all the time,Ive repaired hundreds,and a sled carb works on the same principle of fuel delivery,the pilot jet (they call them slow idle jets on a harley carb) has a very very small opening and if blocked partially or fully will either cause the motor to stall at idle/or bog.
The keihin has a vacuum lifted slide,wheres the mikuni has a mechanical lift,,but to the same end .
The CARB farts you here of are from a lean mix due to a smaller than required pilot.
When you have a bad intake seal generally the whole spectrum from idle to wot becomes lean as the vacuum caused by your big two cylinder air pump becomes greater
Last edited by vincentostapowich; Jan 9, 2012 at 09:56 AM.
Seasoned HDF Member
Joined: Dec 2010
Posts: 7,736
Likes: 1,524
From: Coromandel Peninsula New Zealand
Bad seals can and do present with the symptoms he is describing, especially if only one seal is gone.
Most people won't notice across the board leanness but the carb farts will give it away every time.
Most people won't notice across the board leanness but the carb farts will give it away every time.
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Thread Starter
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Road Master
Joined: Jul 2009
Posts: 849
Likes: 13
From: Santo Domingo, Dominican Republic
well yesterday I had time to go over after hours with my mech at the clubhouse and everything is good now! He didn't do much to the bike but to clean all the contacts of the ignition and mess around with the air fuel mixture on the carb... so no Frankenstein surgery needed this time 