Well it really seems to be related to the efi or ignition system. There's a point in the throttle where I can back off the throttle a millimeter and it will run ok, then push down that millimeter and its running like crap. I've bypassed the PCIII there was no difference. New plugs, clean oil, clean airfilter.
I just pulled the cvt cover off, everything looks fine. Pulled the airbox off and visually checked everything, all looks ok. Pulled the valve cover off the intake side of the rear cylinder, they seem to have about the proper clearance by feel. I wish I had an efi light or something. I guess next is checking each sensor individually.
yeah they all blink once then go out. try blowing the clutch out? they may look clean untill you take an air compressor to them. also is it the orginal belt? is the belt within service limits. and adjusted correctly.. maybe try fuel injector cleaner. just throwing ideas out there
I had the same issue, disconnected my power programmer, cleaned air filter, cleaned carbs and filter and still plenty of low end and then it would start breaking up. Happened to me every time I got on the trail. So I moved to the electrical side all checked good and then it just dawned on me to check the battery. Replaced it and all was normal. Stupid me but last thing I checked. Mine is an 07 with 1500 miles on it. Good luck