I need some help. I have a 2007 Ultra that I bought in March of this year. The bike has always ran perfectly with no problems. Came home from a ride yesterday, pulled into my yard, and the bike started misfiring and backfiring through the air cleaner, sounded like it was running on one cylinder and then quit running. It'll restart, but go back into the same sequence and quit again. Any suggestions on where to start looking at this problem would be greatly appreciated. It's a 96" with stage one, reworked stock mufflers, and XIed's. Everything else is stock. THanks for an ideas.

 

Possible bad wire on an injector.

 

Try taking the XIed's off. If it still runs the same at least you can eliminate that as the reason. Is it throwing any codes?

 

Fuel/air, compression, and spark at the right time. Start with your battery; clean and tight. Unplug ECM, apply dilectric grease, replug. Well you get the idea; it's a slow methodical process which will be speeded up if the bike threw any codes.

 

pull the plugs and check the ceramic inslulator on the tips....sometimes they slide down over the electrode and causes what you are describing

 

OK, just came back from checking it....Made sure it was full and had fresh gas. can hear the fuel pump prssurize and then shut off, checked for any loose connections or wires. Bike will start, run for about 5-10 seconds, backfire through the intake a couple of times, and then stop running.

 

Make sure You are not losing fuel pressure. A quik check is to remove fuel cap and energize the fuel pump. if you see fuel spraying the problem is there.

 

Possibly a sticky idle air control.

 

backfire through the intake causes:

lean mixture ( no fuel/air leak)

advanced timing-( unlikely)

bent valve stem/sticking valve or other valetrain problem allowing intake valve to stay open

or cam problem with timing/ drive


crank position sensor

mike

 

Always check the most obvious and simplest things first. If it sounds and acts like it is running on one cylinder, pull the spark plugs and check if they are any good. Also check the plug wires.