Off throttle backfire

[crofrog]

Originally Posted by K2m

When a LC8 is perfectly tuned they do this.

It may be possible to tune it out by changing the Air Leak jet on the ACV (air cut valve) it's on the pilot circuit.

If you wish to explore this option I can help further.

If I understand correctly :-
It came back from the shop popping on decel. ..... Spot on.

+1 every well jetted lc8 I've been on does it, _and_ it's fun.

[DirtyADV]

Super simple carb sync tool!

Was one of the plugs I had earlier that failed, was plastic and cracked now I going with metal.

/Johan

[kulvershtukas]

Have the same issue. Seems like the right pipe is backfiring. Also seems like it is going hot a little bit faster than the left one. As soon as I am not a real technician, have asked the guy from the service to do 15kt service and check the issues. So far:
- no leaks or cracks in pipes
- no vacuum leaks
- air filter is clean
- carbs are synced
- valves are cleaned, regulated
- Leo Vince cans are checked from the inside
All is in order, nothing wrong with the bike, but it still backfires... I guess it just has to do that

[kulvershtukas]

Also spark plugs are replaced, but have not seen the bike yet

[Sumi]

If it pulls as it should and idle is fine, I'd say it's normal. They really all do that!

If your slides are not in sync (if they are way out of sync I mean), it might be a carb sync issue (way out of sync carbs will also cause backfiring - but probably not just off throttle).

But IMO if it has the power it should have, and the idle isn't hunting too badly neither hanging, then it's normal - the off throttle backfiring. Also it's a better practice to ride these bikes instead of worrying about every hickup it throws at us / repairing (what isn't really broken) it constantly:)

[Aussijussi]

Originally Posted by Sumi

If it pulls as it should and idle is fine, I'd say it's normal. They really all do that!

If your slides are not in sync (if they are way out of sync I mean), it might be a carb sync issue (way out of sync carbs will also cause backfiring - but probably not just off throttle).

But IMO if it has the power it should have, and the idle isn't hunting too badly neither hanging, then it's normal - the off throttle backfiring. Also it's a better practice to ride these bikes instead of worrying about every hickup it throws at us / repairing (what isn't really broken) it constantly:)

+1 I probably fall into 'the worry wart' category too, i think it's mainly due to the avalanche of information the net brings with it. After reading dozens of different enquirys about water pump, clutch slave, fuel pump, clatter at starting the bike, fuel mapping, etc etc.... One starts to imagine all sort's of sounds, coming from the engine. As you said, just ride the frigging thing!
Although i can't, due to snow

[fastdirt505]

Mine definitely backfires under 5k rpm with the throttle closed. I have my spark arrestors out of the FMF pipes which makes it worse. I have to decide if I want heads to turn when downshifting to a stop or not. If I don't want the attention I just pull in the clutch or you can give the throttle just a slight turn to silence the pops. The bike runs great but backfires.

[Groundhog]

Just an idea. I had a lot of popping and backfiring on deceleration on my '07.

Then I (just) repacked my FMFs and almost all of it went away! Imagine that! I had about 12,000 miles on the original packing.

[Zuber]

I haven't read if the SAS is still on this bike. That thing injects air into the exhaust and makes it backfire, just like an exhaust leak.

[K2m]

Originally Posted by Aussijussi

+1 As you said, just ride the frigging thing!
Although i can't, due to snow

You better come back home digga There's a beer in the fridge

[K2m]

Originally Posted by fastdirt505

you can give the throttle just a slight turn to silence the pops. The bike runs great but backfires.

Exactly what I do at 2 in the morning.

I luv it as it swears at the world. Reminds me of racing car cams, feels like them to as you open it up and it springs into life......... Best part of riding this bike in traffic........ Why would you want it to feel/sound like a 1975 Honda CB250.....

[fastdirt505]

Originally Posted by fastdirt505

Mine definitely backfires under 5k rpm with the throttle closed. I have my spark arrestors out of the FMF pipes which makes it worse. I have to decide if I want heads to turn when downshifting to a stop or not. If I don't want the attention I just pull in the clutch or you can give the throttle just a slight turn to silence the pops. The bike runs great but backfires.

I just recently installed the CPR intake and CJ Designs jetting and all the backfiring went away. I am still running the FMF pipes without the inserts. I guess my bike wasn't jetted correctly coming from Florida to Georgia, although it ran fine it backfired. Now the backfiring is gone.