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Sportster Models 883, 883 Custom, 1200 Custom, 883L, 1200L, 1200S, 1200 Roadster, XR1200, and the Nightster.
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  #1  
Old 11-21-2010, 07:26 PM
fyrman1 fyrman1 is offline
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Default 2003 Sportster 1200 backfire sputter and not firing

My 2003 Sportster 1200 just started a problem...hard to start, when i do get it started the rear cylinder doesnt seem to be running...cold exhaust comes out and there is not the normal vroom. Front cylinder seems to be running fine. Choke has to be pulled out all the way. After a minute or two the rear cylinder begins to fire and occasionally backfires. Even when warmed up i have to leave the choke pulled out and rear cylinder backfires every few seconds. Carb cleaner and "sea foam" brand cleaner dont seem to be working. Fresh gas in bike. I have never pulled this carb off. What do i need to do/check before i start taking the carb apart?
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Old 11-21-2010, 07:38 PM
32vld 32vld is offline
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Sounds as the rear cylinder is lean. Vacum leak between carb and rear cylinder head.
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Old 11-21-2010, 08:14 PM
TangoDown TangoDown is offline
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Quote:
Originally Posted by 32vld View Post
Sounds as the rear cylinder is lean. Vacum leak between carb and rear cylinder head.
Ditto. Also, have you checked the sparkplug and/or wire, ignition coil, and module? Could be an electrical problem.
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Old 11-21-2010, 09:23 PM
fyrman1 fyrman1 is offline
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Checked the spark plugs and they are about 3 months old. gap was good but they were both a little wet, even the cylinder that was running correctly. Will check those other items tomorrow.
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Old 11-21-2010, 09:41 PM
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xFreebirdx xFreebirdx is offline
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Plugs do fail....but buy a service manual for your bike and do some serious mait. on the bike. Plus the HD service manual has great trouble shooting guides in it. Plus some good advice was posted above.

This place will help you tune your carb.

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Old 11-21-2010, 09:41 PM
 
 
 
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1200, 1996, 2003, backfire, backfireing, backfires, choke, constantly, custom, cylinder, fireing, front, harley, rear, sportster, sputtering, start


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