Crackling/popping when coming off throttle

[rmg471]

All:

I just purchased a used 2006 FZ6. 20,000 miles. It has been serviced regularly, and is all stock except for the Scorpion brand exhaust and K&N air filter. My question is the following: When I hold steady RPMs around 3K, or when I really rev it above 8K and drop the throttle, I get a crackling/popping sound. If that's OK, then fine, and I'll move along, but I believe from my carbureted offroad riding days, that would mean the air/fuel mixture isn't correct.

I just completely washed and cleaned the air filter (K&N). Brand new engine oil and coolant (not that this matters). Is this normal? Can it be corrected? How do I know if I'm running lean or rich?

I'm good at following directions, I just don't know much about the fuel injection on the FZ6. I appreciate any input and help.

Thanks,

Ryan

 

[ChanceCoats123]

This is normal for most people with an aftermarket exhaust. One of the biggest reasons is that our bike has an Air Injection System that puts clean air from the airbox into the exhaust to burn off excess fuel. This is a purely emissions-based system and can be stopped using AIS block-off plates.

I really like the noise on my bike, but I know some people really don't like it.

 

[rmg471]

I just wanted to make sure that it wasn't hurting the bike. It's good to hear that I'm not alone. Thanks for the quick reply. You guys are great.

 

[QwickFliCk]

I have this problem n I used a copper gasket rtv between each meeting point of the aftermarket exhaust it helped a lot

 

[Zealot]

I get this too.

From what I've read, there's a couple of ways to help reduce it. This was all based on reading what otger people have said on anitger forum, and ive only personally dabbled with the TB sync portion which helped slightly. As I recall...

You can start by ensuring a correct fueling mixture in your bike to compensate for the pipes a bit. Past that, some sort of DB killer or equivalent can help reduce it in addition to syncing your throttle bodies. Lastly, as has already be mentioned in this thread, block off plates.

 

[TownsendsFJR1300]

On my 07, (about the same mileage), I also have open Scorps but the OEM air filter.

I do NOT have ANY de-cel popping. Bone stock short of iridiums, sync within 3mm's per cylinder. Idle is set at 1,100. CO#'s are factory and NEVER been changed. AIR system in place.. Idle varies NO MORE than 50 RPM's, tops..


From what I've read, the K&N will flow more air (and NOT filter as well as OEM) and lean out the mix some.

The K&N air filter vs OEM is one thing myself and FinalImpact agree on.

IMO, I would go back to the OEM filter, maybe check the sync as well as the CO #'s. (I wouldn't necessarily change the CO #'s but if thier all set at say 0, someones screwed with it).

[MENTION=15974]FinalImpact[/MENTION]

 

[ChanceCoats123]

On my 07, (about the same mileage), I also have open Scorps but the OEM air filter.

I do NOT have ANY de-cel popping. Bone stock short of iridiums, sync within 3mm's per cylinder. Idle is set at 1,100. CO#'s are factory and NEVER been changed. AIR system in place.. Idle varies NO MORE than 50 RPM's, tops..


From what I've read, the K&N will flow more air (and NOT filter as well as OEM) and lean out the mix some.

The K&N air filter vs OEM is one thing myself and FinalImpact agree on.

IMO, I would go back to the OEM filter, maybe check the sync as well as the CO #'s. (I wouldn't necessarily change the CO #'s but if thier all set at say 0, someones screwed with it).

[MENTION=15974]FinalImpact[/MENTION]

Also keep in mind that the 07 and newer bikes use an O2 sensor to change the fuel map. 06 and older have no on-the-fly changing to the fuel map like the newer version does. If it's a result of excess fuel in the exhaust, then an O2 sensor would read quite fat and decrease the fuel added.

 

[TownsendsFJR1300]

Also keep in mind that the 07 and newer bikes use an O2 sensor to change the fuel map. 06 and older have no on-the-fly changing to the fuel map like the newer version does. If it's a result of excess fuel in the exhaust, then an O2 sensor would read quite fat and decrease the fuel added.

Yea, I missed the year of his bike and lack of the sensor... :spank:

Good catch, tks.....

 

[FinalImpact]

Best I can tell the S2's only adjust the fueling using the O2 sensor output when the running steady state conditions like cruising. i.e. very minor changes in wrist angle. Simply put - it can't make decisions that fast so it relies on a fuel MAP just like anything else.
The Narrow band O2/ECU arrangement does not make on the fly adjustments when the grip is literally twisted. It runs off its fuel table MAP just like the S1.


What would be entertaining is the Wideband O2 and logger I'm running now - well, if the pipe had two bungs, I could LOG what the Factory ECU map is doing MAP wise. It would be very easy to capture its AFR sequence. Although I could log what it does baseline w/out the O2 sensor. I just need some time and a reason.

On an unrelated note / S2 Dyno Runs and Tuning:
With the S2 bikes having upstream CATs in the header pipes - AND the Tuners tuning with Sensor into the tail pipe; how do they possibly have a clue ABOUT HOW EFFICIENT those CATs are???

Lets say the header CATs are:
100% efficient from idle to 4500 PRM under load! Think in terms of gas volume....
Q? at 8K and 13K 100 WOT are those CATs still 100% efficient at converting unburned fuel to burned fuel? I doubt it!
So then, how does a turner know or compensate unless they get their Sniffer, ahead of the CATs?!!! IMO they must be guessing!
- Its Why I have an S1 header on there. That said, what are these fuel maps on the S2 bikes? 99% of them were ran through a catalyst that did **SOMETHING TO IT** !!! But they don't know what! I need to post this elsewhere... Just thought I'd share some "tweeker thoughts"... lol

Scott,
Rev your bike to 12000 in second and chop the throttle - pretty sure its gonna pop! The POP also has to do with how you ride! More abrupt throttle closure leads to more unburned fuel in the exhaust (crack it quick, close it quick). And with AIS working, from higher revs it pulls in extra air and enough to reburn. No popping says something about how we ride!

 

[TownsendsFJR1300]

Scott,
Rev your bike to 12000 in second and chop the throttle - pretty sure its gonna pop! The POP also has to do with how you ride! More abrupt throttle closure leads to more unburned fuel in the exhaust (crack it quick, close it quick). And with AIS working, from higher revs it pulls in extra air and enough to reburn. No popping says something about how we ride!

I've run that high many times before with NO popping.

I'm going out for breakfest this am and will do a second gear hard pull to 12,000k and chop it.

I'll post in a couple of hours.

 

[TownsendsFJR1300]

Scott,
Rev your bike to 12000 in second and chop the throttle - pretty sure its gonna pop! The POP also has to do with how you ride! More abrupt throttle closure leads to more unburned fuel in the exhaust (crack it quick, close it quick). And with AIS working, from higher revs it pulls in extra air and enough to reburn. No popping says something about how we ride!

Randy,

Three hard runs in second gear (about 84 MPH),

#1 was to 13k, full chop, absolutly NO de-cell (or any) pop...
#2 was to red line, rev limiter kicked in, full chop, still no pop what so ever.
#3 was to EXACTLY 12k, full chop, NO de-cel pop what so ever. Just as
smooth decelerating as accelerating

Again, open Scorps, AIR system stock, all CATS installed, iridiums. I run regular fuel, Yamaha's "Ringfree" regularly along with "Gas Shok". The front wheel was trying to climb into the air in second as well..

 

[FinalImpact]

Randy,

Three hard runs in second gear (about 84 MPH),

#1 was to 13k, full chop, absolutly NO de-cell (or any) pop...
#2 was to red line, rev limiter kicked in, full chop, still no pop what so ever.
#3 was to EXACTLY 12k, full chop, NO de-cel pop what so ever. Just as
smooth decelerating as accelerating

Again, open Scorps, AIR system stock, all CATS installed, iridiums. I run regular fuel, Yamaha's "Ringfree" regularly along with "Gas Shok". The front wheel was trying to climb into the air in second as well..

Maybe only the fast ones crack and pop!!! :spank: BlahBlah
Mine has several adjustments, so its not fair to compare to stock at this point. But it popped when completely stock w/oem muff.

Long as your happy with your's and I'm happy with mine as is - It's all Good! :thumbup:

 

[TownsendsFJR1300]

Maybe only the fast ones crack and pop!!! :spank: BlahBlah

The "funny cars", "dragsters" etc, their ALWAYS CRACKING AND POPPING AS THEY SLOW..

Running at over 300 MPH in 1/4 mile, guess thier "babying it" down the track too!! :spank:

Yep, the fast one's "crackle and pop" (like a cereal), BUT the fastest machines, tuned correctly, (no excess fuel in the cylinders when off the throttle) DON'T.....


Nice try at back peddling thou!

 

[FinalImpact]

LOL ^^ where have we gone here? Race vehicles shooting flames belong here why???

 

[Insanity_rules]

My 04 with standard filter and stain tune exhaust pops and crackles like mad. I absolutely love the sound.

 

[ozgurakman]

My s1 pops when co values are low. I added some numbers to values (+5 to c1 and c2) and now it's so fine, no pops or something funny from exhaust.
Bike is full stock.

 

[TownsendsFJR1300]

LOL ^^ where have we gone here? Race vehicles shooting flames belong here why???
- Exceeding the limits of meds i suspect...

Yea, the meds are too high! BlahBlahBlah

Did you ever get you A/F ratio correct or even on the map, on your bike?

Get rid of the lope induced into the engine?

I haven't found / seen any high end cages (or bikes) that backfire on de-cel when properly tuned..


**You asked me to do a full de-cel from 12k which I did as a favor to you.
It did NOT back fire as you suspected, but de-celerated normally.

If you don't want to hear the results/blow it off/insult my bike, insult me, please don't ask.

 

[FinalImpact]

As stated: I'm happy with mine, however, we ride in very different environments and have different expectations from our bikes. I don't care for the fuel chop when getting back on the throttle in a corner and I took actions to eliminate it. A side effect is it pops and I could care less that it does. If your ride is crackle free, I'm fine with that too!

FWIW: I'm not the one wanting to know why things pop. I simply stated that how we drive/ride matters. A tiny air leak in the exhaust matters. Also as the AFR goes lean past 14.7:1 (i.e. 15:1), the combustion process can be more efficient and there is even less fuel to reburn.

On the topic of TUNE: I'm going to agree to disagree and here is why; Properly tuned has different implications. An example might be economy vs full out performance. The tune is different for each. I've witnessed flames from the exhaust of cars and bikes as performance increases. In these cases its likely NOT a stoichiometric 14.7:1 AFR, but something much richer to assist the vehicle during acceleration/peak loads. So pick a topic and stay on it. Are we talking this bike in stock trim or dragsters shooting flames?? Totally different vehicles and applications. Things making flames...

On Topic: Thanks! If I had to guess "why" your does not pop, it **may be ** because the idle speed setting at 1100 = LESS AIR in the mixture to create a reburn. That said, the AIS (air induction system) should be opening and allowing air in so, I don't have a reasonable explanation. This isn't for me, but set the idle to 1350 and repeat the tests. See if that changes anything. As you've stated, clearly it changes the "engine braking factor". Some may not notice while others do. I find it very noticeable and agree the LOWER is better for MORE engine braking. So clearly the tiny amount of Ari we speak of matters. Is it enough to cause the difference between those that pop and those that don't (No CO mods, Fuel Controllers, but With Slip On pipes????). Maybe?