[Dr. N. Field MC]

As of late, My G-5 with 25k miles (K&N air filter - made in England pee shooter muffler) has taken to backfiring loudly  when I back off the throttle. I use no OH gas & have run a couple of tanks of injector cleaner. Fuel comsumpsion seems to be unchanged (65 to 73 mpg on the open road at 60 or less mph). I don't know how to run diagnostics on the EFI and I don't want to replace parts willy-nilly.

[NorthernMonkey]

Mine does that. It sounds awesome.

[shamelin]

Loose exhaust header?  Bad header gasket?

[barenekd]

Or loose manifold/injector connection.
Bare

[Royal Stargazer]

I'll have to keep an eye on this thread. I've been getting some backfiring as of late, too. EFI silencer (battle damaged,) and K&N filter.

It's not loud, and it's not constant, but for the first time last saturday she backfired just as I kicked her over. Hope it's not a sign of anything sinister on the horizon.

[tresser4K]

Pull in the clutch when releasing throttle, or don't release it all, or do it very slowly
and the popping will stop.  Not technically backfiring, that is when flames come out your carb.

[wildbill]

all 3 efi mufflers i had backfired on the uce - some more than others

[tresser4K]

I really don't mind.  Gives it an authentic vintage bike sound.

[2bikebill]

Same as Bill, my aftermarket silencers all backfire now and again - Hitchcocks efi, occasionally; Watsonian Goldie, more, but also the best overrun growl I've ever heard; Indian Electra silencer, lovely thump but constant massive backfires, unusable.
It may be that the stock silencer pops as well, but too quiet to notice...

[barenekd]

My EFI would backfire (Afterfire for the technically based ones) occasionally. Did on perfiect timeing one day. A guy ran a stop sign if front of me as he was turning off a side street onto the street I was on, going my way. I had to brake for him which kinda pissed me off. As I rode past him I kinda gave him the "EvilEye" and he added a bit of throttle to keep up with me. As he started pulling alongside of me, my bike issued a great "POW" and, man, did that dude ever back off! Musta thought I took a potshot at him! I had to crack up at the look on his face.
See, more smiles per mile all the time!
Bare

[no bs]

have you never turned the ignition off underway, and then turned it back on to scare the crap out of cagers? do not attempt at home!

[Sectorsteve]

Love a little backfire but when it decreases performance its not good. I sealed some gaps at the muffler/header connect and after that all is well.

[Desi Bike]

have you never turned the ignition off underway, and then turned it back on to scare the crap out of cagers? do not attempt at home!

About twenty five years ago I was a school bus driver for a short stint. I had a full sized school bus fueled by propane. The bus roe I had in down town Toronto would go through a fairly long underpass. At least once a week if shut the ignition at the start of the tunnel and pump it a few times before turning it back on.   The exhaust pipe was a four inch diameter thirty foot long cannon.   The kids loved it. Lol

[no bs]

yeah, a decent blast but i can't recommend doing it too often.

[barenekd]

Useta retard the timing on my BSAs to get that noisy response!
They were loud! I usually was running straight pipes, anyway.
Bare

[Ducati Scotty]

Mine never did this with the stock muffler but all the aftermarket ones I've tried do it now and again.  Usually just a *pffffft*, but once in a while it sounds like a gunshot.  Must scare the people around me, it scares the hell out of me!

Scott

[Craig McClure]

have you never turned the ignition off underway, and then turned it back on to scare the crap out of cagers? do not attempt at home!
[/quote
After I bent the family car in 1964, the body shop loaned us a 1952 Chevy, It had a tendency to hiccup any way, Which my high school buddies found amusing, I found I could get a big backfire & plenty of attention turning the ignition on & off, which I did quite a few times. Unfortunately several of these backfires were through the carburetor. The air cleaner was in the trunk because the heap would stall when it was in place. Everything was fun & games until a huge bubble resembling a cheese pizza formed on the hood - yes we were ON FIRE. Every body bailed out, it was blazing pretty good at the side of the road & no one had a anything to smother the fire. We tried to flag down a passing policeman but he must have been off duty. By this time it was quite a blaze. Eventually the fire department did arrive before the tires caught fire. Scratch one toasted 52 Chevy. Think I was the only kid in high school to wreck 2 cars in one week.

[Dr. N. Field MC]

Exhaust is tight. I've been running this muffler for 20,000+ miles. (though the baffles have been loose and shaking around inside for the last 6 or 7k). Performance seems to be about the same. Still banging away. Planning on more injector cleaner.