Mechanics! bring your ears on that. I need you

[klingklang]

What is doing this exhaust annoying puff? I checked for leak, headers gasket, joints..niet.  any idea?

https://drive.google.com/file/d/0BzCOvRAEOcgCNWUtekNIYnd5b00/view?usp=sharing

[JoeDirt]

If you have another muffler/TOR can to try... or can bare to run without the muffler with ear plugs in for a short time. It sounds like an exhaust leak or something lose in the muffler to me.

[benebob]

Ditto but doesn't sound like any Triumph triple I know.

[thebiglad]

When I first heard it (the noise) it made me think of engines that run with 1 cylinder down. What do you guys think, only running on 2?

Cheers
Dave

[Timbox2]

I was getting a similar sound when I had a hole in one of the IACV tubes

[JayDub]

I was thinking valve clearances or timing?

[klingklang]

think I found,  Timbox wake me up. I've had to change to iacv valve (rusted) last spring and lost  my settings. I had few back pop too.  I took the computer and raised the CO a bit and it reduce it, So I raised it until it stop but now my RPM is about 1300-1400. I'll wait a bit to stabilize  CPU set itself a bit and will try to go lower on IACV value to reduce rpm.