carb pop?
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Intermediate
Joined: Jun 2013
Posts: 41
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From: Indiana
carb pop?
My 2006 sporty 1200 some days has a pop that comes from carb occasionally when slowing down and coming to a stop then when I give it some gas to take off sometimes it pops up out of carb. Dosent seem to matter on the times it does it if its warm or cold. Bike is stock except for exhaust. Also added screaming eagle plug wires. But did before that as well. Worry about it or don't?
Seasoned HDF Member
Joined: Jul 2011
Posts: 27,096
Likes: 4,673
From: Frozelandia, Minnysota
When you put an aftermarket (usually low backpressure and loud) on a carbed Harley it's going to run lean. Common, easy fix is a size up on the low speed jet and re-adjust the mixture screw. If you're really familiar with carbs, you can raise the needle, but that's more complicated and requires pretty much a teardown of the carb. It's "normal" because more folks put on loud pipes than don't, and many of them think that's all they have to do to make it run faster. It won't, you lose mid range torque without further work, and it pops - that's from a lean mixture. Harleys run about as lean as they can from the factory, so any leaner isn't doing your bike any favors. If it had the exhaust on it when you bought it, it may have been re-jetted already; look under the carb (probably need a small mirror) and see if the plug covering the mixture screw has been pulled out; that's a sure sign somebody's adjusted it, and it might only need a little more. I've got two carbed sportsters, both had loud pipes, one with no carb work and ran really bad, the other had the necessary tweaking and ran just fine. When I put a larger jet in the first one and adjusted the mixture, it ran just fine afterwards, more power and real smooth.
Other things like an intake leak can make them pop, too, but the most common cause when aftermarket pipes are installed, is the lean running carb. If you don't know already, your 06 sporty is the last year with a carb.
Other things like an intake leak can make them pop, too, but the most common cause when aftermarket pipes are installed, is the lean running carb. If you don't know already, your 06 sporty is the last year with a carb.
2nd Gear
Joined: May 2013
Posts: 6
Likes: 0
From: east coast
No problem. I was worried the first time mine did it. Mine rarely does it, just randomly when coasting then i roll back into the throttle. I have 1200kit, screamin eagle exhaust and intake and it was dyno tuned before i got it from the dealer supposidly although i never got to see a dyno sheet.
As has been said, carb farts on low rpm roll on is an indication of too lean. Either find the leak or adjust the carb. Ez fix either way.
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Cruiser
Joined: Mar 2008
Posts: 197
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From: Grey Duck
Just remember every carb adjustment is a compromise. Many, many factors are considered in a well tuned carb, some you can control and some you cant. Air temp. and humidity are two factors you cant control. If you have your carb tuned perfectly when its 95° it will be lean at 40°,not a big deal, just the way it is.
When you decel, there is all kinds of hell going on between that hot cylinder and that hot exhaust pipe. We add fuel/decrease O2 to the mix for that RPM range to correct that pop.
FI systems can change with the known variables but as soon as you change one of the constants (air intake, exhaust pressure) the system needs to be corrected as well.
I like carbs myself, they're inexpensive to set up and once they're properly set up you can give the mixture screw a little turn when needed.
BTW just to be clear, It's not that Harleys come from the factory so frickin' lean, every vehicle sold in this country is. You take the air filter off and cut the muffler off of a Yamaha or your Ford Focus and guess what....
When you decel, there is all kinds of hell going on between that hot cylinder and that hot exhaust pipe. We add fuel/decrease O2 to the mix for that RPM range to correct that pop.
FI systems can change with the known variables but as soon as you change one of the constants (air intake, exhaust pressure) the system needs to be corrected as well.
I like carbs myself, they're inexpensive to set up and once they're properly set up you can give the mixture screw a little turn when needed.
BTW just to be clear, It's not that Harleys come from the factory so frickin' lean, every vehicle sold in this country is. You take the air filter off and cut the muffler off of a Yamaha or your Ford Focus and guess what....
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Road Warrior
Joined: Jun 2010
Posts: 1,882
Likes: 83
stock carb, stock settings, never changed jets. More so when cold then when warmed up. After 5 years I just consider it personality. I may get bored and change jets one day but It purrs like a kitten when its warmed and well that's all I can ask for. My plugs show normal so i' good.