I haven't participated in the forum in a couple of years, but I'm still racing the 2011 675R and still loving the bike. Hi again to everyone who's still around.
I crashed at my last race meet, and since putting humpty dumpty back together again I've had a new issue with the bike. It runs fine throughout the rev range, except between about 2000 and 2500 RPM. In that range it stutters and stumbles, and will stall if I'm not careful to rev it out and slip the clutch.
It felt like a fueling issue, so I cleaned and re-oiled the MWR air filter, dropped new spark plugs in, cleaned the fuel filter and swished out the tank, and used fuel from a different petrol station. The problem still persisted after that, so I installed TuneECU on my phone (my laptop with TuneECU is long gone), did some poking around.
What I found was that the Manifold Absolute Pressure for all 3 cylinders drops to zero in the problematic rev range. Here's some TuneECU screen captures:
So I swapped the MAP sensor with the barometric pressure sensor (they're the same unit), and the same problem persisted, so I don't think it's the MAP sensor itself. All the hoses seem to be connected well.
Has anyone seen this before and solved it, or have any ideas where to look next?