Bloody backfiring

[DBRacingGod]

Right. I've got a 2000 1150GS. I bought it with a cat-less Y-piece and a stock can. Only trouble is - it backfires like a bastard on the over run. I've fitted a PC to try and tweak it out (77bhp and 70lb ft BTW), and set it up on a dyno to optimise the fuelling, but no dice.
Is this typical or should I start fishing around for a leak in the system somewhere?
Thanks,
DBRG

 

[Schtum]

With the engine running at idle, plug the outlet of the exhaust can. Does the engine die or does it keep running? If the latter, then you've got one or more leaks in the system. The full Remus system on my 1200 has got a leak and it backfires like a bastard on the overrun.

 

[cookie]

my 2000 1150 loves to backfire on the overun, annoys the feck out of me

had the whole exhaust off 3 times now, never found the leak

coming off again as soon as i get time.

 

[Welshman]

My beast 1150 GS (first reg 9 / 9/ 1999) also backfires, but maybe cos I have the cat still on but run it without any tail pipe, purrs in town at 1/4 throttle and roars like a beast wide open!

This is Africa, no blue meanies checking for noise!

Welshie

Better to remain silent and thought a fool, than to speak out and remove all doubt .

 

[DBRacingGod]

Cool, wildo. Hello Schtum, nice to see you again, away from the dog-raping maniacs on supermotard.

 

[(RIP) Kaister]

its not the exhaust system leaking causing the backfire.

unburnt fuel doesn't necessarily need air to ignite it - just a spark.

see the techlusion website

 

[cookie]

its not the exhaust system leaking causing the backfire.

unburnt fuel doesn't necessarily need air to ignite it - just a spark.

see the techlusion website

i'd like to agree with that as i have no detectable leaks. the BB powerchip bloke says otherwise however

 

[DBRacingGod]

I'm probably going to sound a bit controversial here, but why trust Techlusion, which states that you don't need to run the thing on a dyno to check its fuelling over a PC, which is professionally set up by a top tuner? I wouldn't trust the stock downloads from a PC either, I'd always ask to get my bike properly fettled on a dyno to check what's occurring.
I think there's a sodding leak by the Y-piece...pass the liquid metal, Seymour.

 

[allan]

my 2000 reg 1150GS gargles and pops on the overrun but I love the sound so holes or not I will not be fixing it.

 

[(RIP) Kaister]

more clues from Dobeck........


What is a false idle?
The correct answer is - Anytime the bike idles with out the proper air/fuel ratio

You can take an engine idling and turn out the mixture screw, causing the RPMs to decrease. You then can go the other direction lean causing the RPMs to decrease. So if I re-adjust the idle stop screw each time, I could have two different settings and each of them holding 1000 RPMs. But the true idle would come when I maximize the air-fuel and adjusted the throttle stop to the 1000 RPMs.

If under acceleration or steady throttle I have back firing out of the exhaust is it?
The correct answer is - Electrical

A disruption in spark is the cause of a pop, out of the exhaust on acceleration. However, richness can cause the spark plug to foul, which then leads to the disruption and then a pop.

Bikes with fuel injection shut off their injectors on deceleration?
The correct answer is True

Yes, however not during warm up and most all turn their injectors back on in the last 20% of their rev range. If you are real sharp, in second take your bike to redline, and shut the throttle. While coasting try to pick up the point when the ECU turns the injectors on. Harley turns on at about 2900 RPMs. Can you hear yours?