Backfiring

[hackers2r]

So I searched but my situation is a little more specific.  The bike is an S2R 800 with full Arrow exhaust, Nemesis ECU, DP airbox and filter.  Bike has been dyno tuned and makes plenty of power (69 at the wheel)  However, I only get backfiring around 2750 rpm on decel.  In addition, while checking for leaks which I found none, the bike is shooting out flames once in a while but only at the same 2750 rpm.  Any ideas?

[Porsche Monkey]

Sounds lean.

[hackers2r]

I agree...but the bike has been on the dyno 4 times since everything was installed.  They insist the fuel/air is good.

[Howie]

Double check for exhaust leaks.

[DarkStaR]

Can you post up your dyno sheets with A/F readings?

[booger]

They insist the fuel/air is good.

what do the plugs say

[hackers2r]

Gonna check that later today.

[Heath]

what is the easiest way to check for exhaust leaks?  I mean you can't put your hand up to the exhaust too hot.

[hackers2r]

I use tissue paper and check for movement while blipping the throttle.

[psycledelic]

I had about the same situation on my 800.  It turned out to be an exhaust leak from a flubbed up Termi weld (like that ever happens).  It was kind of hard to find because it was in between the two S pipes.  Not sure that was the only issue.  I dropped my entire exhaust and reinstalled after I had the weld fixed. 

[hackers2r]

Issue solved.  Tightened up the vertical cylinder header and backfiring went away.  Amazing it can be something so small!