Prolific Poster Award
Join Date: Jul 2010
Location: Grass Lake, Mi, USA
Does it happen under no load , just bringing up the revs while sitting still ? You understand how to make it backfire, cutting the spark momentarily causing an unburnt fuel build up in the exhaust. But why would an intermittent spark only be happening at WOT ? The only thing that comes to mind is the ECU, which you did play with . The other thing would be an exhaust leak contributing to this.
'96 Ducati SS900CR, '07 S4RS, '06 Busa, '77 Bonny,
'00 Superglide, '85 Sportster, '78 SR500