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Getting a pop on start-up

flhtdan

Member
I get a pop out of my left exhaust on start up every once in awhile. My local shop said it was intake gaskets and replaced them.
Still pops. Any other ideas on why it does that?
 
More info would be helpful such as what mods if any have you done to your scoot.
What is every once in awhile?

The more info you give will help in figuring out what is causing your issue.
 
It's a 2004 flht, EFI, that has 38,000 mi. on a 95 in. big bore kit. It has a medium size cam (Don't know the size). True duals with SE mufflers. A SE Pro Super Tuner
It pops about every 10th or 12th start.
 
Cool air getting sucked into the exhaust from a leak can do that.
1 thing you can check is for an exhaust leak by using a couple rags folded over to thicken them but large enough to cover the outlet of the muffler at first start up. With someone covering the side that pops, start the engine and quickly listen at all connections for any air leak.
 
Is this a relatively new issue? Could be an air leak. Does your scoot seem to run rich or lean? ie does your exhaust smell gassy? Could be unburnt gas/fumes in the exhaust that linger after shut off.
 
First, just because the intake manifold gaskets were replaced doesn't mean there is no leak; check for an intake leak and eliminate that potential source first. Were the intake seals replaced as well? Another potential source of an intake leak. That's the obvious and first place to look; check it out and let us know what you find.;)
 
Jeff brought up a good posability of lingering fuel in the exhaust.
I had a 03 RoadKing that once in awhile would pop on cold start up. What I noticed was that sometimes right befor I shut the engine off if I didn't allow a couple seconds of idle time the following morning The engine would often do the pop / slight backfire at first start.
Might be worth alowwing a short idle befor shut down.
Could be that simple.
 
I took the bike back in to my local shop to see if there were any other leaks and they just scratch their head. They suggested maybe old exahust. My mufflers do have 115,000-120,000 miles on them. They suggested switching them out with another pair and see if it still happens. Not going to do that. I'll wait and see if it gets worse and take it to a better shop I know, but it's 90 min away.
 
Leaking exhaust gasket can also cause a pop. Had that problem on my 95' Heritage softail. Popping through one side. Changed the exhaust gaskets and it stopped.

It definitely helps to have good mechanics looking at it. Some of the so-called bike mechanics here in my town are clueless. Not sure how they got the job really. Good luck brother.
 
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