Ducati Monster Forum

Moto Board => Tech => Topic started by: hackers2r on May 16, 2010, 06:06:37 AM

Title: Backfiring
Post by: hackers2r on May 16, 2010, 06:06:37 AM
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?
Title: Re: Backfiring
Post by: Porsche Monkey on May 16, 2010, 06:15:50 AM
Sounds lean.
Title: Re: Backfiring
Post by: hackers2r on May 16, 2010, 06:31:10 AM
I agree...but the bike has been on the dyno 4 times since everything was installed.  They insist the fuel/air is good.
Title: Re: Backfiring
Post by: Howie on May 16, 2010, 07:19:52 AM
Double check for exhaust leaks.
Title: Re: Backfiring
Post by: DarkStaR on May 16, 2010, 07:23:28 AM
Can you post up your dyno sheets with A/F readings?
Title: Re: Backfiring
Post by: booger on May 16, 2010, 07:37:14 AM
Quote from: hackers2r on May 16, 2010, 06:31:10 AM
They insist the fuel/air is good.

what do the plugs say
Title: Re: Backfiring
Post by: hackers2r on May 16, 2010, 09:07:17 AM
Gonna check that later today.
Title: Re: Backfiring
Post by: Heath on May 16, 2010, 09:14:49 AM
what is the easiest way to check for exhaust leaks?  I mean you can't put your hand up to the exhaust too hot.
Title: Re: Backfiring
Post by: hackers2r on May 16, 2010, 09:17:08 AM
I use tissue paper and check for movement while blipping the throttle.
Title: Re: Backfiring
Post by: psycledelic on May 17, 2010, 04:19:23 AM
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. 
Title: Re: Backfiring
Post by: hackers2r on May 18, 2010, 01:42:04 PM
Issue solved.  Tightened up the vertical cylinder header and backfiring went away.  Amazing it can be something so small!