M1100 pulse air injection?

[dennisd]

Does the Monster M1100 have a pulse air injection system?  The dealer had already installed the Termignoni "race" slip-on system which includes the tuner and air filter.  I get deceleration pop with the baffles in but it becomes annoying with the baffles removed.  Before I start looking for leaks in the exhaust system I thought I'd find out if the bike has a fresh air injection system; I know from experience a PAIR system will cause deceleration popping.

Matter of fact, I'm on my way out to my garage now to block off the PAIR system on my '09 Kawi Versys.

[Slide Panda]

It's probably just a leak. I've got no idea if it's got that injection - but I doubt it. It's quite common for folks to get the pop when they swap cans, or shortly there after.

[Raux]

no. but it does have that exhaust valve for noise regulations. the slipons are after that valve. not sure how it works, but probably not your issue.

cycle your bike on and off 3 times without starting. i think that resets the TPS. may be a small issue.

personally, i love that decel noise 

[ungeheuer]

no. but it does have that exhaust valve for noise regulations. the slipons are after that valve. not sure how it works, but probably not your issue.

Yup, not your issue, the flapper valve is - AFAIK - for static noise testing and as such only functions when in neutral, does absolutely zip when on the move.....

personally, i love that decel noise 

+1,000,000 

[dennisd]

Thanks for explaining the exhaust valve.

I thought it was like the system used on some Japanese sport bikes.  On theirs, it closes slightly at lower rpm to help the low end torque then opens at higher rpms to flow free to help get max horsepower.  I didn't think the flapper valve was the source of the deceleration popping.

Some vehicles use a system (called a PAIR valve by most) to inject fresh air into the exhaust circuit to help burn hydrocarbons.  This will definitely cause deceleration popping with a free flow exhaust.  Actually, it causes popping with the OEM quite system but you just don't notice it because it's quite.

I already bought some exhaust sealant in a tube.  I plan to remove the slip-ons and put some on the pipe to silencer junction.

[sroberts152]

i noticed this (And was actually thinking about it today on my ride to work on my 1100) when I had my 696 and installed the Termi Slip ons.  My 696 used to pop like hell after the Termis went on.

Someone correct me if I'm way off here, but you could try removing the slip ons and putting some sealer around where the slip ons attach.  I think the air leak is there since nothing else really changed.  I did the slip ons, rode to the dealership where they did the TPS, ECU and filter and it popped as soon as the pipes went on.

[Raux]

obviously there are a couple of things that come with the race only termis. one... no cat and a computer running richer. both those probably attribute to the popping. the TI termi system is road legal with cats and probably doesn't have the issue.

[dennisd]

i noticed this (And was actually thinking about it today on my ride to work on my 1100) when I had my 696 and installed the Termi Slip ons.  My 696 used to pop like hell after the Termis went on.

Someone correct me if I'm way off here, but you could try removing the slip ons and putting some sealer around where the slip ons attach.  I think the air leak is there since nothing else really changed.  I did the slip ons, rode to the dealership where they did the TPS, ECU and filter and it popped as soon as the pipes went on.

I already thought about that.  The junction only overlaps about 15 to 20mm.  I bought some exhaust sealer in a tube but I'm going to wait till my fender eliminator arrives in case I have to take off the silencers to get to bolts when replacing that.  I'll post here afterward with the results.

[Scissors]

Popping on deceleration is normal, even on a properly tuned engine.  It happens on stock systems, but is less obvious because the mufflers do a good job of, well, muffling the noise.  There are several possible causes but generally, interestingly enough, it is a combination of a lean condition and a rich condition.  Running lean on-throttle heats the exhaust more than it would be if you were running rich.  However, snapping the throttle closed but leaving it at higher RPM (engine braking) forces the cylinders to suck in more air from the exhaust pipe because of the higher vacuum, which in turn results in incomplete combustion and a rich condition.  The unburned fuel hits the hot exhaust and ignites again in the pipe, causing anything from mild popping to outright "gunshots".

Air injection systems which add air to the exhaust gases also cause popping as their purpose is to burn the unburned hydrocarbons in the exhaust.

Even when your engine is tuned for maximum performance, exhaust popping is still going to happen and under-muffled pipes are still going to make it louder.  It's simply normal for a 4-stroke piston engine.


For the record this is not a backfire as those, by definition, are when the flame front (fire) burns backwards into the intake.  Thus the term "backfire."  Fire in the exhaust is an afterburn, not a backfire.

[dennisd]

Sissors, I pretty much know everything you explained.  You will notice, I said deceleration popping not backfire.  It makes me "smile" when I hear someone say backfiring when they talk about post-burn popping or deceleration popping through the exhaust.

I agree, some popping is just unavoidable and I also agree that it does it with the stock exhaust but you just can't hear it as much.  However, I think mine is doing it much more than normal.  I actually have heard it on several of my bikes with the stock exhaust.  My Versys has a PAIR valve and I will be blocking it off since I now have a Scorpion silencer on it.  I also believe fresh air makes the pop much louder than it would be if the system receives no fresh air through the PAIR or exhaust leaks.  Thats why I asked about the air injection before I started looking for a leak on my M1100.  I've had to block off the air injection system on several Japanese bikes I've had.

I believe mine is the victim of fresh air entering the exhaust.  I plan on starting with the silencer to pipe junction and working from there.