Whats causing the backfire?

[Krayy]

Okay you motorheads, heres one for you...

On deceleration, every now and then I get a noise from the can. It's not a bang, but more of a loud huff, if you get my drift. The Q is what could be causing it?

[Hitcher]

Okay you motorheads, heres one for you...

On deceleration, every now and then I get a noise from the can. It's not a bang, but more of a loud huff, if you get my drift. The Q is what could be causing it?

You've got a curmudgeonly KiwiBiker senior member stuck in there?

[Devil]

You've got a curmudgeonly KiwiBiker senior member stuck in there?

Get back in the can!

[Blakamin]

Air leak in your pipe somewhere....maybe at the header end....

[Krayy]

Air leak in your pipe somewhere....maybe at the header end....

Any ideas on what to use to seal it, or will I need to remove the can to replace the gaskets(if any)?

[vifferman]

It's flatulence.

Try using a fuel with a lower bean additive count.

[Blakamin]

have you looked near the collector for any little holes? normally visible by little black soot marks... would have a careful inspection of all pipe joins and bits that get near the ground before pulling shit off

Any ideas on what to use to seal it, or will I need to remove the can to replace the gaskets(if any)?

never had a look at your bikes setup... on in-line 4's its easy....normally just unbolt the header, clean area thoroughly, add squished copper ring (or whateva your gasket is) and refit... might be different on your "V" .... dunno...

[Sensei]

Can be unburnt gases igniting inside the exhaust system .
SENSEI

[White trash]

Okay you motorheads, heres one for you...

On deceleration, every now and then I get a noise from the can. It's not a bang, but more of a loud huff, if you get my drift. The Q is what could be causing it?

Dunno. Butr the '04 R1 thingy we have here does exactly the same thing.

[Blakamin]

Dunno. Butr the '04 R1 thingy we have here does exactly the same thing.

thats coz they belong to hair-dressers... they like a little "poof-poof"
Oh... he hasn't traded it yet has he....

[loosebruce]

It's flatulence.

Try using a fuel with a lower bean additive count.

Ohhh chilli beans, bad memories, one peice leathers, bad gas.......

But yeah, check ya seals, may have a small nick of crack somewhere in ya system, is it hot or cold when it does it. Maybe running slighty rich.

Could be a number of things, jsut gotta eliminate each one.

Ah a TL with a/m pipes off the throttle, brublling and back firing away, beautiful, pity it'll be a while beofre i hear that again.

[guzzi_nz]

Can be unburnt gases igniting inside the exhaust system .
SENSEI

this is what cause my guzzi to badly back fire on d-rev :sly: bike was flooding

[bear]

Noticed mine does that a bit more after moving to a higher octane fuel.

[McJim]

Okay - I've got the same problem with my Ducati 600 except it sounds like South Central Los Angeles on a Friday night. Tonight I had Maverick following me part way along the motorway and he called me later to say I was getting about 15cm flames every time it backfired.

So is it a leak in the pipe or is it running rich?

And if it's running rich how do I make it run leaner?

By the way I've been running 91 ron in the bike.

[Conquiztador]

Here: http://www.gnttype.org/techarea/engine/plugs.html

That will give an indication re if she runs rich. If the answer is yes, then fit a smaller main jet. You can also drop down the needle a step or two. But this will only change the amount of fuel up to about 1/2 throttle. And you might find that she does not accelerate eavenly anymore. If that is the case, then put needle back where it was and change to a smaller main jet.

Other possible reasons:

- Ignition timing
- Air leak in exhaust. Could be a hole somewhere or where exhaust fits on to head.
- Poor ignition. Fuel is not burnt properly as spark is weak and is then burnt inside exhaust. Swap plugs and se if fixes problem.
- Not sure re your bike, but if battery is needed for ignition, then could also be poor battery/poor charging. This will give low voltage to coil and create poor spark.

Or if bike worn, then could be a combination of them.

Good luck.