OK, had a bigger look / play today
No water in filler neck, so that would seem to eliminate the water / fuel scenario
It ran fine for the first 9 miles , but i mad a concious effort to
blip the throttle at junctions, to keep the revs above 1500 ish
No problem, the bike seemed fine --
On the return trip, i rode normaly , and the misfire thing was
back. Oddly enough, it seems to be at 3K as you come onto
open throttle, the engine gives a big cough as if its going to
stall, so you give it some more throttle, and it clears its head
and charges off.
Unsettling if your trying to filter and ride smoothly out of a
roundabout at low gear!
Throttle body balance? plugs / coils or fueling issue?