Bang Bang Pow Pop Pop mmmmmmmmm

[Cameronhall]

What essentially is back firing, and is it a good thing or bad? I have a 2006 FZ6 stock air fiter and M4 exhaust. Letting off the throttle produces a (see above in title) loud glorious popping sound. Input any one?

 

[degake]

Get yourself a PC III usb and do a TB sync, it will make a huge difference. :thumbup:
Your bike is running a bit rich (and out of sync) due to the changed airflow with the aftermarket exhaust. It isn't too bad for the engine (otherwise they would state it in the installation manual of the exhausts).
You could eventually play with the CO values in DIAG-mode as well, but power commander + throttle body sync will be your best bet (and get it dyno'ed for the best results :flash: )

Grtz,


Degake

 

[Ransom]

Is that fixable with just an upgraded air filter? Would that happen because it isn't breathing in as much as it is pushing out? I upgraded my air filter at the same I installed my aftermarket exhaust so I am just wondering if I would have had the same problem if I didn't upgrade both at the same time.

 

[Cameronhall]

Get yourself a PC III usb and do a TB sync, it will make a huge difference. :thumbup:
Your bike is running a bit rich (and out of sync) due to the changed airflow with the aftermarket exhaust. It isn't too bad for the engine (otherwise they would state it in the installation manual of the exhausts).
You could eventually play with the CO values in DIAG-mode as well, but power commander + throttle body sync will be your best bet (and get it dyno'ed for the best results :flash: )

Grtz,


Degake

And for those of us who are clueless can you dumb it down for me. please..

 

[dxh24]

I believe that backfiring, iirc can be due to the wrong amount of backpressure on the valves. Correct me on that if i'm wrong, it's 7am and i'm on about 3 hrs of sleep, alot of things make sense to me right now that shouldn't

As others have said, a PC or similar product with the right tool....Which i believe fixes it because your getting the right amount of fuel/air and hence the right amount of backpressure (?)

 

[ChevyFazer]

I Was under the impression that backfiring in his situation is from a lean condition and when you back off the throttle the exhaust is still trying to move large amounts of air while the engine is not. Basicly your engine and exhaust are not on the same page adding more fuel should help

 

[McLovin]

Fz6 backfires, you just hear it more with with your pipes..

 

[Cameronhall]

My rx8 has Ram air intake, hi flow filter4 to 1 head, dual res cat, and dual exhaust, ie. high dolllar straight pipe and when i shift gears at high rpms i blow a reasonably sized fire ball. but when down shifting it doesnt back fire but every one in a blue moon.

[ame=http://www.youtube.com/watch?v=82RpDScjaXM&feature=plcp&context=C3261b52UDOEgsToPDskKHraeH5OEUVwS8gNfZvBuN]Rx8 full racing beat exhaust - YouTube[/ame]

 

[SovietRobot]

This (most commonly) is the sound of the Air Injection System working.
It injects air into the exhaust stream during off idle conditions and when it combines with the unburnt fuel at the hot catalytic converter, it combusts making the popping sound.
Essentially it's an emissions thing.

 

[Andz]

I find that mine backfires when cold at the elevation I live at (5,500ft amsl) but when warm it stops. When I was on holiday in Cape Town which is at sea level it popped more vigorously and during all throttle-off conditions.

 

[jerdman89]

I added an k&n air filter, a pcIII, and an m4 exhaust on mine all at the same time. At first I was running a zero map so no change to fueling and got the backfires you are talking about. Then I synced a scorpion map because it seemed to be the most similar exhaust and the back fire went away for the most part. It still does it on occasion, mostly letting off the throttle hard at high rpm but not as bad. A dyno tune would be best but it works.

 

[DeusEx]

I had the same backfiring issues at first, when I installed my Leo's with BMC air filter but without pcIII or Co adjustments. While decalerating it happened a lot.
As I figured out, it was due to lean air/fuel mixture. That means that there was more air than fuel injected through the air filter.

I solved the problem by adding more fuel in the Co adjustments. Needs a bit experimenting but it's free!

PS: Read through this thread
http://www.600riders.com/forum/fz6-mods/4809-dyno-tune-co-adjustment-leo-vince.html

 

[TownsendsFJR1300]

Get yourself a PC III usb and do a TB sync, it will make a huge difference. :thumbup:
Your bike is running a bit rich (and out of sync) due to the changed airflow with the aftermarket exhaust. It isn't too bad for the engine (otherwise they would state it in the installation manual of the exhausts).
You could eventually play with the CO values in DIAG-mode as well, but power commander + throttle body sync will be your best bet (and get it dyno'ed for the best results :flash: )

Grtz,


Degake

I believe in the US, the option of changing the CO settings isn't possible (or available in the Diag settings). I do know in the FJR (in the US) you have to "hotwire" (Barbarian jump as its known in the FJR community) the ECU to change the settings. Elsewhere in the world, Yamaha allows you to play with the settings.

For those not aware of the CO settings, it changes how much fuel is added at lower RPMs. Should you change them, its a good idea to record the original #'s should you need to go back, their usually not all set all the same...

As for the op, you may try re-setting the computer (disconnect the battery for at least 10 minutes), it may help. I put open Scorps on my 07 with no other changes, (no computer re-set), and it doesn't pop or backfire whatsoever. I have the TB's synced within 2mm's of each other, factory allowance is 10mm. The Scorps have some pretty wide cans(W/O DB killers-cat still installed).

Also, +1 on the throttle sync, it'll help no matter what can's you have on it. I strongly suggest obtaining your own manometer for syncing. The Yamaha shop, for my FJR (before I bought my own Morgan Carbtune) adjusted a butterfly (from the factory, the butterflys have a line of white paint over the screw and spring, mine was obviously adjusted approx 1/4 turn which I put back), a strict No No, air screws only.

Yamaha charged over $100 to screw up my bike, the Morgan was about $80 delivered to my door from England. Its paid for itself many times over. I know the TB's are adjusted alot closer than most Yamaha dealers would set them at..

I am at sea level BTW...

 

[ChevyFazer]

You can adjust the co settings but you have to do the same thing by jumping it out

 

[YZF73]

This (most commonly) is the sound of the Air Injection System working.
It injects air into the exhaust stream during off idle conditions and when it combines with the unburnt fuel at the hot catalytic converter, it combusts making the popping sound.
Essentially it's an emissions thing.

I'l second this :thumbup:, fitting an aftermarket exhaust makes this combustion noise audible, depending on which type of aftermarket exhaust is fitted you may get a slightly different noise (my scorpions give a crackle when I drop off the throttle from about 5-6k rpm).

If you are getting a louder, more defined pop, you are probably backfiring, however I'd have thought this would be quite unlikely with the mods you've got.

Yamahaboyz

 

[Phil_RC_1]

Definitely the AIS, it's an easy fix!! and a common issue after installing a high flow exhaust on almost all newer bikes.

The AIS injects air into the exhaust to allow any unburned gasses to burn off before they leave the exhaust. It's an emmissions thing. It's kinda like having an exhaust leak.

No need for all the expensive PCIII modules or Co adjusting or sync'ing. These things are good, but not the real issue for the popping!!!

Click here for a full AIS removal tutorial. However, there is an easier simpler way. Find the hose that runs from the airbox and feeds the AIS, remove one end, insert a marble or wooden dowl, or any cylindrical piece that will fully plug the hose, if your insert isn't quite tight you can use a small hose clamp to insure that no air leaks by your plug, then reinstall hose. Basically, if the AIS system can't suck in the fresh air, it can't inject it into the exhaust, problem solved.

If anyone fixed this popping by adjusting thier A/F ratio's, and didn't block-off the AIS, you are now WAAAAAAAAAAAAAAAAAYYYYYYYYYYY rich at low throttle positions. I would suggest that you remove or plug the AIS and then properly retune.

FWIW: "IF" the AIS has been blocked, popping on decel is typically a lean idle mixture (for carbs), or lean idle setting (CO) on the EFI module.

 

[SovietRobot]

Definitely the AIS, it's an easy fix!! and a common issue after installing a high flow exhaust on almost all newer bikes.

The AIS injects air into the exhaust to allow any unburned gasses to burn off before they leave the exhaust. It's an emmissions thing. It's kinda like having an exhaust leak.

No need for all the expensive PCIII modules or Co adjusting or sync'ing. These things are good, but not the real issue for the popping!!!

Click here for a full AIS removal tutorial. However, there is an easier simpler way. Find the hose that runs from the airbox and feeds the AIS, remove one end, insert a marble or wooden dowl, or any cylindrical piece that will fully plug the hose, if your insert isn't quite tight you can use a small hose clamp to insure that no air leaks by your plug, then reinstall hose. Basically, if the AIS system can't suck in the fresh air, it can't inject it into the exhaust, problem solved.

If anyone fixed this popping by adjusting thier A/F ratio's, and didn't block-off the AIS, you are now WAAAAAAAAAAAAAAAAAYYYYYYYYYYY rich at low throttle positions. I would suggest that you remove or plug the AIS and then properly retune.

FWIW: "IF" the AIS has been blocked, popping on decel is typically a lean idle mixture (for carbs), or lean idle setting (CO) on the EFI module.

I would also suggest that if you're going to block off the AIS instead of completely removing it, to disconnect the electrical connector from the AIS valve so it's not opening and closing all the time for no reason.

 

[crimsonrick]

I bought a used 2009 FZ6 2 years ago. The previous owner had installed a PC5, KN air filter and 2 Brothers exhaust. When I leave work every afternoon, the highlight of my day is the sound of my exhaust when I roll up to the stop sign leaving work. That glorious popping and snapping gives me chills every time. I don't care about correcting it, if it's a flaw. I guess I don't have enough excitement in my life, lol.