reasons for bike to pop on decel

[muskrat]

I swear it's an exhaust leak because it sounds funny but not being mechanically inclined I thought I'd ask for help/input from you guys so I can start shaking down the bike. 
I have an 06, S4R with about 7,500 miles.  She's only popped when it gets below 40 so I thought maybe she's running lean, and I haven't changed the sparkplugs either.....yet.

let'r rip

[ducpainter]

Exhaust leaks were pretty common on those bikes.

I believe it was the front header to pipe gasket...

this link should help...http://ducatimonsterforum.org/index.php?topic=12501.0

[Speeddog]

Did it just start popping recently, or has this problem been around for a while?

[muskrat]

this is the second time and last ride it did it once or twice.  this time more pronounced.  I've never had an issue with it before.

[JonnyCinco]

poor air fuel ratio.  can happen especially with aftermarket slip-ons.

happens on my S3 all the time

[muskrat]

but it's never been a problem before so I can't imagine it's a fuel/air mixture.

[battlecry]

What do you guys recommend to seal the pipes?  Was thinking of some teflon tape or teflon packing by the slip ons but what do you do by the front cyl head? 

[gage]

What do you guys recommend to seal the pipes?  Was thinking of some teflon tape or teflon packing by the slip ons but what do you do by the front cyl head? 

You can use High temp Copper RTV on any slip joints and the headers have gaskets which you could replace and add RTV if you are paranoid about them leaking again.

[Slide Panda]

I had this crop on my 620 after a while... just loosening the connections, giving it a wiggle and re tightening everything sorted it.

[Bill in OKC]

Sounding funny - check the little plugs in the exhaust.  My bikes have had one for each cylinder, I think they are for testing exhaust gasses.  I've had them come out - lost on the road somewhere and when they are gone, it will sound funny and pop on decel.

[JonnyCinco]

but it's never been a problem before so I can't imagine it's a fuel/air mixture.

"running lean" is an air/fuel ratio problem.  It is not doing any harm to the engine, unless you do have something loose.  but you were saying that is only happens when it is cold, so I do not think it is because something is loose.

Linkie for support

[gage]

"running lean" is an air/fuel ratio problem.  It is not doing any harm to the engine, unless you do have something loose. 

I completely disagree with this statement. Fuel plays a critical role in cooling and lubricating the engines valves, piston walls etc. and a lean running engine is a bad thing risking damage to engine internals and leaving power on the table.

To the OP: What octane are you running? Since this is only doing this when cold you are most likely running lean because as JonnyCinco points out colder air is denser.

Try putting a higher octane fuel in the engine to see if that helps offset some of the popping.

You can also pull the plugs and look them over white is bad - brown is good

[muskrat]

I'll loosen and re-tighten to see if that fixes the problem.  as for the fuel/air mixture, I run 93 in my tank always. 

[cduarte]

the octane has nothing to do with your air/fuel mixture... if your bike has an 02 sensor (not running a DP ECU), then try getting a fatduc to richen your mixture.

[gage]

I'll loosen and re-tighten to see if that fixes the problem.  as for the fuel/air mixture, I run 93 in my tank always. 

93 is not needed in our engines under most circumstances.

Do you have an open airbox or slip-ons?

I would be curious to see the plugs or you could just not worry about it...