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Aftermarket Exhaust popping

D

daytien

New member
Joined
Sep 29, 2011
Location
East Bay
Moto(s)
Ninja 300,
600 CBR F4i, ninja 250
I am currently riding a 2013 fuel injected Ninja 300 non abs. The previous owner swapped the stock exhaust with a WERKS USA slip on.
WERKESNinja300Kawasaki2013.jpg


I get a popping/afterfire? sound whenever I release the throttle after accelerating decelerating.
I did some research and I have successfully minimized it with fully closing the throttle/pulling in the clutch when decelerating, but I was worried about this popping harming the bike in any way.
I read something along the lines of the fuel being too rich or lean, but does installing the slip on do that?
Would I get better performance out of the bike with a stock exhaust installed?

Distilled questions:

1. Does the slip on affect any of the interior components negatively/positively?

2. Is there loss/gain of power with installing the slip on without performing a tuning with it?
(if yes) Can I tune it without going to the shop?
(if no) how much does it cost to do this?

3.Is there anything I can do to make performance better w/ slip on or better without?

I'm a longtime viewer, but first time poster so if there are tweaks to be made let me know. Thanks =]
 
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Your bike is already probably leaned out from the factory. Adding a slip on will lean it out even more and that's what's probably causing the popping / back fire. Look into a fuel management device like Dynojet's Power Commander. They have fuel maps to help smooth out your air/fuel ratio. Running lean can cause your engine to run hotter than normal and in extreme cases I've heard it can burn your valves.
 
Make sure the joint between the slip on and the exhaust collector is tight and not leaking. Air slipping into this joint between exhaust pulses will vause popping.
 
Your bike has an air injection system (AIS) that puts extra air into the header of the exhaust to help burn any unburnt fuel for emissions. A freer flowing exhaust will cause the AIS to pop like crazy. My FJ-09 with Akrapovic exhaust and AIS sounded like a popcorn machine. My WR250X also popped a lot with its aftermarket exhaust till I installed an AIS blockoff plate.

Getting the bike tuned might not be a bad idea if you plan on keeping it long term. A lot of factory tunes are a bit too lean anyways for emissions, so adding the exhaust probably isn't helping.
 
Generally exhaust popping does not harm the motor. My ZX14 does it. I like it, kind of sounds GP-ish. Follow the advice of the previous posters. You could take a look at your spark plugs. Should be a light tan. If they are white you're running lean. Then I'd recommend a reflash or Power Commander.
 
yeah, I bet it's the air injection and it needs to be blocked off.

all your neighbors must love the sound.
 
dkcwenge said:
Your bike is already probably leaned out from the factory. Adding a slip on will lean it out even more and that's what's probably causing the popping / back fire. Look into a fuel management device like Dynojet's Power Commander. They have fuel maps to help smooth out your air/fuel ratio. Running lean can cause your engine to run hotter than normal and in extreme cases I've heard it can burn your valves.
Click to expand...

^^^ Good advice there; as well as the above posters. Yes your bike already runs a bit lean due to emissions standards nanny's (CARB.) The AIS they've mentioned also leans everything downstream of the head/exhaust port to assist bike(s) to pass emissions standard testing.

I've experienced this many times on many bikes; removing a restriction to the exhaust (full exhaust "header," or muffler/baffle) will always cause popping. On racebikes/high-performance street bikes; we almost always use a aftermarket "block-off" plate, or just remove all the emissions crap & weld up the port.

For YOUR bike a re-map/re-flash is required to get the mixture back where it belongs for the most power/cooler running. That should get rid of the pop & make the bike run cooler, & better. You'll likely get a few ponies (HP) too. Just get it done & you'll be a happy camper...

-ebd
 
A tune would be good but not 100% necessary with a new muffler. If you install a Ivan's emissions block off kit that should eliminate 95% of the popping.
 
I had an Akrapovic exhaust on my Ninja 300. Feel like the popping went away after a while.
 
Start with the blank off plates and see how it goes. Most folks report a huge reduction in popping when this is done. After that see if your needs/budget/purpose warrant a re-flash of the fuel map. Even if you went back to stock I would install the blocking plates. CARB makes the manufacturers fuel them that lean.

My experience with slip-on mufflers is generally they make little to no extra power. They do make a lot more noise and screw with the fueling a little. If your looking for a pipe to get some more pep out of the bike get a full header. The header is where it's at. At that point you will definitely need to do some fueling work. YMMV.
 
JimE said:
Start with the blank off plates and see how it goes. Most folks report a huge reduction in popping when this is done. After that see if your needs/budget/purpose warrant a re-flash of the fuel map. Even if you went back to stock I would install the blocking plates. CARB makes the manufacturers fuel them that lean.

My experience with slip-on mufflers is generally they make little to no extra power. They do make a lot more noise and screw with the fueling a little. If your looking for a pipe to get some more pep out of the bike get a full header. The header is where it's at. At that point you will definitely need to do some fueling work. YMMV.
Click to expand...

Header is more for weight loss than anything I think... he could get a similar effect by drilling out the Catalytic converter
 
Thanks for all the advice/pointers. I'm pretty new to tuning/flashing and the sort. What would be an average cost for performing one? I'm not sure if it is within my budget as of right now. Would it be more cost effective to just replace the exhaust back to the stock?
 
It's a Kawi thing.

Does it do it at one particular RPM on decel? My ZX14 with a full exhaust, block off plates PC5 still did it at EXACTLY 3500 rpm with the throttle closed. It's a Kawasaki emissions thing. As I recall the explanation was that the fuel and possibly the spark was cut on decel with the throttle completely closed, then at 3500 rpm it came back and the un-burnt fuel in the exhaust ignited causing bang. With out the cat in the system to silence it it was quite loud. If you pull in the clutch it kept the spark and fuel going by tricking the bike into thinking it needed to maintain idle. If it does do it at exactly one rpm try just cracking the throttle as you pass through that range.


Dennis
 
So, the popping you are hearing is not back-firing. It is a popping
resonating sound generated by a lean condition on decel. When you
suddenly close the throttle, the incoming air is choked off and the
closed throttle also causes the bike to return to idle on the very
lean idle circuit . However, momentum of the bike is
actually "driving" the engine in a sense, and that engine is still
spinning at rpm that needs far more gas than the closed throttle
can provide. The engine is still spinning but the incoming fuel rate
is very low, until just enough builds up in the combustion chamber to
"fire" on the exhaust stroke of the engine.

To know this for sure, the next time it happens, pull in the clutch
and the popping will stop immediately, because the bike's momentum is
not pushing the engine to spin. All in all its not problem, because popping is not
at all damaging to the bike. So don't expect your dealer to fix the problem
under warranty because it is not a warrantable situation. The EPA drove this
more than anything else.
 
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^^^^This. :thumbup

Even bikes in great tune can pop on decel. You can spend a lot of money and time chasing the popping but you aren't going to get a night and day improvement to running.

If the popping on decel doesn't bother you , don't worry about it.
 
...for me it was always about going to a FULL exhaust system for weight reduction being the primary goal. I would later tune for performance; & as mentioned- it may not "cure popping" entirely. Depends on who is doing the tuning, what brand pipe, & of course, =the quality of work.

For some, noise is where it's at= thus a can/baffle/muffler change like yours. I think this is mainly for those (US mid-west/south) that live far from ANY curvery, & only go to "bike-nights" & other meets. Bike gotta sound right for those ya-know. :rolleyes

Most exhausts are designed to lighten the bike, increase engine note(?), & lastly improve performance. I've had bikes that responded hugely to this mod (ZRX1100/ZX12R), & others that didn't (kz650), once tuned correctly.

If your budget is tight & you can't afford to get a mixture controller (like the DJ Power Commander), you might want to consider just going back to stock can for now. As your ability/experience improves, you may start to feel the need to enhance performance. THEN do a "full-exhaust" for weight reduction & performance when you can afford it AND the pro tuning to get it working right. IMHO/FWIW :ride

All the best, -ebd
 
I like the popping on deaccelleration. To my ears it's music. I had it happen once on my ST when one of the smog systems, probably the air injection system, developed a leak and extra air got into the exhaust system. I fixed it by junking the smog stuff. Then later on when I decided to try some D&D cans for a while, the popping returned. As I know my bike was in perfect condition and I'd fattened up the slow/main jets and raised the needles (confirmed perfect jetting on a dyno), I guessed it was because the D&D pipes simply didn't muffle the sound as well as the stockers and I had the popping all along, I just couldn't hear it with the stock cans. I went back to the stock cans, though, 'cause the D&D cans were just too damn loud. I HAD to wear earplug when riding and because it sounded like an RC45 race bike, I was rapping it out to redline all the time. Not good for safety.

Interesting note: When I got my JCW Mini, I found it had a very nice exhaust burble when I let off the throttle. I found out, though, that it was engineered into the car on purpose. When lifting the throttle, the computer delivers just enough fuel to cause the burble for 3 or 4 seconds and then shuts it off. It's a nice addition to my driving experience.
 
Just installed my new akra on my 300 a few weeks ago from Christmas and it does the same thing. I noticed popping with the stock it's just more noticeable now. Only happens when I let engine braking take over a lot.
 
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