Leaky exhaust

[BBQ Chef]

When I was washing the Tuono today I noticed some carbon on the outside of the pipe where the slip-on (stock) meets up with the pipe. It wiped clean but it led me to believe that the two pipes do not make a tight fit. Sure enough, when I started it up, water was spraying out and I could feel exhaust escaping.
My questions are: Could this condition contribute to the popping on decelleration and does anyone else have the same problem?

[pastajet]

I don't have the leak but I do get that popping/backfire sometimes, it's usually subtle. It started when I went to the Akra slip on. Doing the de-restrict nor adding the better air filter made any difference.

[Manu]

Originally posted by BBQ Chef
When I was washing the Tuono today I noticed some carbon on the outside of the pipe where the slip-on (stock) meets up with the pipe.
I also noticed some deposit at the very same spot... I'm gonna check if the leak is noticeable or not.

On the popping thing, yes fresh air inlet could increase exhaust gas "post" combustion and thus popping.

Mine (stock derestricted) doesn't really pop, but I can hear the exhaust note getting louder on deceleration when the tach needle hits the 3500-3000 rpm zone. I'm guessing this could be due the following: At high RPM the ECU must cut fuel injection when throttle is closed on deceleration, but to avoid stalling FI probably get back around 3000 rpm and that might be the cause for some popping.

Do you guys get popping higher than 3-3.5 k rpm ?

Also I noticed that a tiny little throttle opening (most of the time done without even noticing it) on deceleration is usually enough that get some popping, if you close it back popping usually disappears.

[Manu]

I've checked mine as I was coming back from work, and it appears I got the same leak. Guess it's there since my dealer derestricted the slip-on.
I don't think this cause any problems to the engine or performance wise. I checked the workshop manual and there's no gasket or O-ring involved. Cures could be: Wait until deposits fill in the leak or a few rubber hammer knocks at the right place. :D

[Tuono Tex]

If the bracket around the body of the muffler is not in the right place it can keep the pipes from seating all the way. I'd check this first.

[Micah / AF1 Racing]

All slip joints will leak a bit for the first few thousand miles...my Mille did too but after some time it all seals up perfectly. This is common to all slip joint style exhaust connections...cars, bikes, race boats whatever....

Your Touno ALWAYS had popping in the pipe, almost every motor on Earth does....you just will not hear it with a stock exhaust system in place. That popping is unburnt fuel and air "cooking off" in the exhaust system usually after closing the throttle....totally common as well. The only way to eliminate this is to set up the efi program to deliver no fuel at all in closed throttle position above a certain rpm range. My Porsche 944 turned off fuel all together at 0 % throttle until 1500 rpm where it turned the fuel back on so the car would settle into an idle situation. Most bike efi does not use this feature because it contributes to what people call "abrupt" throttle response off the corners.

[BBQ Chef]

I'm not worried at all about the popping. My 95 Speed Triple pops like crazy on decelleration without any problems.

Thanks for the info on the slip joint workings.

[Tuono Tex]

The poppoing may not be a problem.

But, just for the record:

I've got the Aprilia race can and chip on my Tuono. Not once, in 6000 miles, has the bike ever popped or back fired.