Ducati Desmo 900 backfires

[Rocky]

I would appreciate it very much if anyone can provide me with some information as to why my Ducati Desmo 900 backfires when down shifting. Right when the clutch lever is fully pressed in just before down shifting it, it makes one popping sound. Just one good pop. Strangely through,when rolling off the throttle or chopping it does not cause it to backfire. Only when down shifting is involved it backfires.

Now this does not happen every time the bike is being down shifted, but it happens frequently. It also backfires frequently after down shifting has been completed and the clutch lever is let out. Aside from this problem, the bike runs perfectly. The bike starts good, throttle application and response is crisp. There is no hesitation or flat spots when accelerating.

The bike does have a slip on Vance & Hines pipes, and not a full system. The first step to correct this problem, I tried using Ferracci and Ducati performance ECU chips and yet it continues to backfire....


Dennis

[nickatnite]

The first step to correct this problem, I tried using Ferracci and Ducati performance ECU chips and yet it continues to backfire....
Dennis

That is the problem...


You need the K & N FPK Flux capicator. It helped mine....

[Save-the-Manatee]

I had a similar problem on my old Duc that started when I switched to the Scorpion exhaust. The problem could be tweaked out with FI mapping and/or timing adjustments. My guess is that the back pressure profile has changed - one problem with slip-ons is that the rest of the exhaust line has not been optimised to match it - perhaps the main reason folks go to a "full system".

[Juice]

I have to agree with Crimson tide. When doing exhaust mod's, the jetting or FI mapping needs to be adjusted. The main cause of backfiring my guess is lean conditions.


I had a similar problem on my old Duc that started when I switched to the Scorpion exhaust. The problem could be tweaked out with FI mapping and/or timing adjustments. My guess is that the back pressure profile has changed - one problem with slip-ons is that the rest of the exhaust line has not been optimised to match it - perhaps the main reason folks go to a "full system".

[Juice]

I would also look for a exhaust leak. It could be sucking air causing a backfire.

[Drivin&Cryin]

+1 Be sure that you are not sucking air.


I would also look for a exhaust leak. It could be sucking air causing a backfire.

[Craig]

Have you checked your plugs?

Mine pops alot when my plugs get dirty ...