Back fire???
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Elite HDF Member
Joined: Jan 2006
Posts: 4,357
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From: The Lone Star State
Back fire???
After installing new pipes, SE A/C Kit, and having the dealer install the download. I have a minor back fire on deceleration. It is very minor but I notice it. It doesn't really bother me but I just want to be sure this is not going to cause any damage to the bike. What do you guys think?
Outstanding HDF Member
Joined: Sep 2005
Posts: 2,386
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From: Johnston County, NC
RE: Back fire???
It seems like a common cause of leaks in the exhaust is the bolts not being torqued down enough at the exhaust manifold (or whatever it is called on a bike... Sorry... I work on cars.)
Road Captain
Joined: Oct 2005
Posts: 690
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From:
RE: Back fire???
I'm having the same problem too after installing Vance & Hines Big Shots. Even with new exhaust gaskets, the bike pops and cracks on deceleration.
Maybe I need to tighten the nuts down a little more. I don't have a torque wrench so how tight should I go? Everything seems to be snug, no leaks when it's pushing the exhaust out.
While we're at it ... can a loose fitting exhaust contribute to poor fuel mileage? It seems that after the installation, my gas mileage went in the toilet. I've got the Power Commander III and the right (me thinks) map for my bike, air intake and exhaust.
Maybe I need to tighten the nuts down a little more. I don't have a torque wrench so how tight should I go? Everything seems to be snug, no leaks when it's pushing the exhaust out.
While we're at it ... can a loose fitting exhaust contribute to poor fuel mileage? It seems that after the installation, my gas mileage went in the toilet. I've got the Power Commander III and the right (me thinks) map for my bike, air intake and exhaust.
Tourer
Joined: Jul 2005
Posts: 422
Likes: 0
From: Brookville, Ohio
RE: Back fire???
As I see it: If you change things to get more air in and out of the engine you must richen the mixture with more fuel to avoid running too lean. More air plus more fuel equals better power but less fuel economy. I've seen posts where economy will drop from 40 MPG to 29 MPG after intake and exhaust changes. Better performance costs more than just the parts.
Tourer
Joined: Nov 2005
Posts: 412
Likes: 1
From: Cape Canaveral, FL
RE: Back fire???
You're too lean. The factory download is lean. The Big Shots are poor performers and are given to backfiring and popping. You're going to need a DFO to richen the mixture.
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From:
RE: Back fire???
I've always heard a minor popping on decel is normal, as long as it's not on accel. I've heard harleys for years and years let off the gas and give off minor pops. Now a loud backfire is another story........
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Tourer
Joined: Mar 2006
Posts: 341
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From: Richmond, VA
RE: Back fire???
ORIGINAL: GrayRider
You're too lean. The factory download is lean. The Big Shots are poor performers and are given to backfiring and popping. You're going to need a DFO to richen the mixture.
You're too lean. The factory download is lean. The Big Shots are poor performers and are given to backfiring and popping. You're going to need a DFO to richen the mixture.
I have Big Shot Staggered with quiet baffles, Ness Big Sucker and PCIII on my 2002 Heritage Softail Classic. No other mods. I am making 77 HP and 83 torque per the dyno. I wouldn't say they are poor performers. I get some gurgling and maybe a few quiet pops if I get off the gas completly after accelerating hard. I am happy with them.
Tnicean
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