Originally Posted by Sumi
Backfiring into the TB can lead to this. Actually this is the only thing I can imagine that gets carbon buildup inside there:) Didn't your mate notice backfiring into the airbox / cutouts / farts? :)
Anyway.. check the seating of that TB (look for a torn boot) and if the vac. ports on the intakes are OK. (no torn vac. hoses for example)
Did i mention the guy is dazzled with the bike?
Brand new to him...
Took it for a spin and it doesn't feel like missfire, maybe with closed throttle engine braking there is some exhaust backfiring but can't really assure if there is into the TB's.
Been once on the 950 with an intake torn boot and felt it, but not this time. Taking the TB's out.