I've never seen this before, but seems to me there must be only a couple things to check (or is it never that simple?):
At rest, with the airbox off, the bike runs fairly well, and seems to rev cleanly up towards red line OK. But none of the carb slides are moving up more than a few mm's. All 4 cylinders appear to be firing OK - checked exhaust manifolds at idle with an IR thermometer and all are within maybe 10 degree (F) of each other.
I cleaned all the carbs last year and replaced all the intake boots. I checked carefully when putting them back to be sure they all seated properly before tightening the clamps. If this were an isolated carb I could think of a few things to check, but all 4?! Not surprisingly, there is little power past mid revs .
At rest, with the airbox off, the bike runs fairly well, and seems to rev cleanly up towards red line OK. But none of the carb slides are moving up more than a few mm's. All 4 cylinders appear to be firing OK - checked exhaust manifolds at idle with an IR thermometer and all are within maybe 10 degree (F) of each other.
I cleaned all the carbs last year and replaced all the intake boots. I checked carefully when putting them back to be sure they all seated properly before tightening the clamps. If this were an isolated carb I could think of a few things to check, but all 4?! Not surprisingly, there is little power past mid revs .