Why does my exhaust pop? : V-Twin Forum: Harley Davidson Forums

lowrider92 · 07-08-2009, 07:33 PM

when i engine brake the exhaust makes all of these popping noises, i have 11-1 compression with a cv, i have a 195 main jet and a 50 slow speed i had a 55 in and it still popped...and no money for s&s...i have a partially enclosed cone for the intake, and i have straight pipes on it now

engleg · 07-09-2009, 10:57 AM

I read in a motorcycle magazine where three people wrote in asking why they had popping and backfiring out of there exhaust when they decelerated. The magazine tech said one of the most common causes was an air leak between the exhaust pipe and the cylinder exhaust port. I would check to make sure your exhaust gaskets are good, bolts tightened, maybe even adding some kind of a high temp silicone or exhaust sealant around the flange.

TXCHOP · 07-09-2009, 11:08 AM

Well from my experiances with exhaust popping is sometimes you can get rid of it with carbs, sometimes not.

You have a CV carb. Adjust the idle mixture screw in or out. Try a size up pilot and down and adjust the screw again with the different jets. Best to try on a dyno, but not always easy.

Of course make sure there are no intake and exhaust leaks. Strait pipes are not helping the situation any either.

Texas Tom · 07-10-2009, 09:21 AM

It pops because of the way you have it setup ,you like the way it sounds and runs? Don`t engine brake......problem solved...Not meaning to be a smart !!! ,well maybe, anyway with that setup and straight pipes if you have no exhaust leaks no leak at intake it is allmost impossible to eliminate exhaust poping you will drive yourself nuts trying and when your done it will still pop some and you can`t pass a gas station...JMO..Tom..

KingofCubes · 07-10-2009, 09:41 AM

I have a 113" R&R equipped S&S engine with straights that pops on decel like yours without using tranny brake. Love the sound, no leaks, and it will pop your eye balls to the back of your skull.

claydbal · 07-10-2009, 09:57 AM

randy, you need help man. but thats just an OPINION.

tomv · 07-10-2009, 10:20 AM

snap and crackle werent available...nothing wrong with a little poppin...reminds people youre around....

love that sound...

fowler12 · 07-10-2009, 01:38 PM

I agree 100% with Engleg. I had the exact same problem with my 97 heritage. Replaced the exhaust gaskets and it purrs like a dream now with no backfire or popping. Almost a guarentee to fix your problem.....and cheap too!

JustDave71 · 07-30-2009, 08:14 PM

I've dealt with this on my bike, always worse on 90+ hot days. At one point my exhaust was loose at the heads, then I was running too lean. now it just crackles a little bit here and there and, well...I kinda like it actually.

dog155 · 07-31-2009, 09:39 AM

I always loved that sound when I ran straight drags or the next thing to them.It's a Harley thing Man!Riding at night is pure pleasure for the light show with straight drags! Enjoy

tjhogg1 · 08-03-2009, 10:05 PM

is your gas fresh?i had some popping in my s and s 124 with 11-1 comp,630 woods cam,ported and polished headsand mukuni 48 running a vance and hines indy comp 2 into 1 pipe...i was running some vp fuel that was stale...changed the fuel back to 91 oct and problem solved...but i was able to adjust it with the idle/air mixture screw