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Off idle backfire on 1200 c

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Old 06-30-2006, 04:24 PM
CoolRide CoolRide is offline
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Default Off idle backfire on 1200 c

Hello all. I think I might have done an intro but I drink quite a bit so sorry If I didnt. I just dont remember.

I just purchased a 05 1200 C with 981 miles on her. Has the SE exhaust and aircleaner? upgrades. (done by dealership)

My dealership is about 90 miles away and I didnt test drive it. Just looked it over and bought it.

On the drive home I noticed an off idle cough or backfire at about half the red lights I pulled out of.

In the week and a half I have had it I have put 500 miles on it and it does it about 1/2 to 3/4 of the time leaving from a standing stop.

In fact it has backfired and died in the middle of an intersection twice! A little unnerveing to say the least.

I find if I rev it a tiny bit and slowly at the light it takes off just fine, it seems to be when I flick the throttle from idle.

I will take it to the dealership as soon as I can, but being almost a 200 mile round trip AND I have to figure a way back if I have to leave it there, I thought I would ask you guys and girls and see if you have heard of anything like this before, first.

I have had one other Harley years ago a beat 74 sportster I could rarley get to run.

Im afraid Mrs.C. will make me go back the.....dare I say it...Yamahas if we have another flame out in a busy intersection!

Aside from the stupid cough, this has been a great bike. Wonderful in every way, lovin it.

Thanks for your time.

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Old 06-30-2006, 04:59 PM
JohnK/Pa JohnK/Pa is offline
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Default RE: Off idle backfire on 1200 c

If the dealer did the exhaust and filter upgrades hopefully they did the required rejet. if you want to you could look under the carb and see if the plug that hides the idle air adjustment screw has been removed, if it has then most likely they rejetted the carb and if you use a mirror you can look up inside the hole and see the screw. You can turn the screw counter clockwise to richen it up a little usually go about 1/4 turn at a time and see if this helps. The best advice I can give you is to read and reread the DIY section fuel and carb related on Jetting the CV carb if you follow those articles you should not go wrong. Let us know how you make out.
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Old 06-30-2006, 05:21 PM
austinls austinls is offline
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Default RE: Off idle backfire on 1200 c

I have the same bike and did the upgrade myself. Follow the suggstions above to richen the idle. I went 1/4 turn at a time, quickly cracking the throttle after each turn to see if the carb coughs out the intake. When it didn't cough, I quit adjusting.
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Old 07-01-2006, 12:16 AM
12Stones 12Stones is offline
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Default RE: Off idle backfire on 1200 c

Ditto to the posts above. Let us know when you get it worked out. I'd like to know what the cause and solution is.
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Old 07-01-2006, 08:42 AM
AZFlyingDiver AZFlyingDiver is offline
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Default RE: Off idle backfire on 1200 c

If all else fails (good info above), you might also want to check for an intake leak.
It can happen, especially after doing Stage 1 (and removing/reinstalling the carb in the process). It can cause those off-idle carb farts no matter what you do to the idle mixture screw. I know - it happened to me (saw it on the dyno as an overly lean condition right off idle to a few hundred RPM over...)
Do the WD-40 or propane trick for a leak check (sprayed in the manifold area behind the carb while the engine's running - if the tone changes, ya got a leak) - there's also a procedure in the manual.

Good luck - and as has been asked - let us know how it turns out for you!
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05, 111, 1200, 2006, backfire, backfires, backfiring, dies, exhaust, harley, idle, motorcycle, regular, sportster, ss, xl883c

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