Backfire - pop!

[memphis]

Hi, just a quicky - every now and again my bike backfires with a bit of a pop, if honest it don't really mind it - I class it as part of the charm!

But, that said, will harm the bike / engine in anyway?

[Uncle Odd]

My Dyna does it all the time. Been told its the stage 1 tune/screaming eagle II pipes. Who am I to argue?

[Dodzi]

Originally Posted by Uncle Odd

My Dyna does it all the time. Been told its the stage 1 tune/screaming eagle II pipes. Who am I to argue?

It where you've managed to out fox the ECU and its pumped a little too much fuel in and its hit the hot exhaust and pop!

You used to get it a lot on old carb'd bikes but the ECU shouldn't let it happen. Guessing its just not sampling quick enough! Shouldn't do any harm - you can spend a lot of time tuning the ECU to get ride of it. I quite like it - gives it a bit of character!

[banquo]

Normal if on over-run and Stage 1. Engine turning much faster than at tickover, but only enough fuel to sustain tickover, as throttle is closed. Result is weak mixture, which doesn't brun properly in cylinder, enters pipes, and eventually explodes in there with a pop! Character...

[b0nio]

Mine is exactly the same with the Screamin Eagle mufflers, Ok with the stock exhausts.

[Nick69]

Originally Posted by b0nio

Mine is exactly the same with the Screamin Eagle mufflers, Ok with the stock exhausts.

I found that with mine aswell, does not really bother me

[Urrell]

Originally Posted by memphis

Hi, just a quicky - every now and again my bike backfires with a bit of a pop, if honest it don't really mind it - I class it as part of the charm!
But, that said, will harm the bike / engine in anyway?

Is the "pop" out of the carb or exhaust ? Does it happen on acceleration, steady speed or deceleration and is the bike carb or injection ? If it happens at a steady speed or acceleration does it hesitate ?

[memphis]

Hi all – thanks for the all response I can ride in peace knowing the odd pop is doing no harm :-)

Its only really pops if I accelerate hard, I don’t really notice any lags in performance. Mind you I’m not the quickest chap on the block!

Oh, and the bike is a 08 Nighster/injected.

pop pop

[harleyshrew]

Originally Posted by memphis

Hi all – thanks for the all response I can ride in peace knowing the odd pop is doing no harm :-)

Its only really pops if I accelerate hard, I don’t really notice any lags in performance. Mind you I’m not the quickest chap on the block!

Oh, and the bike is a 08 Nighster/injected.

pop pop

Yea its great aint it. happens on mine mainly on deceleration, and I am pretty slow as well

[banquo]

Originally Posted by memphis

Its only really pops if I accelerate hard, I don’t really notice any lags in performance.

That's altogether different. Popping on deceleration (over-run) is normal. Backfiring during acceleration is not, and as mentioned above, you need to be specific about whether it's spitting back through the intake, or backfiring through the exhaust.

Backfiring in exhaust indicates unburnt fuel being passed though and ignited by the hot gases. That could be many things, but is often caused by misfiring, such that one change of fuel doesn't ignite during the power stroke, and is exhausted, unburnt, into the exhaust. Usually caused by an ignition problem, in its simplest form by a duff or fouled plug, plug lead, bad coil or connection, etc. I'd take a look at the plugs, clean and gap them (or replace if they are due) remembering to grease the threads with Copaslip or similar, and torque correctly.
Spitting back through the intake's a wole different ball game. Possibly an air leak at the manifold, or weak mixture setting...

If it's definitely doing it on acceleration then something is wrong IMHO...