Try our new info resource - "Aladdin's Cave" (Main menu)Just added a separate link to Ash's Dropbox thread (shortcut)
I would be tempted to go on a dyno. Might cost a bit more but at least you will have a full read out of what the engine is doing across the entire rev range and this will give you a chance to make small adjustments whilst you are there to potentially fix the problem.
Short update after today's test ride (~50 miles)Issue is present in wide range of RPMs, I confim it from ~3500 revs ->Simply, when at whatever revs I'll open trottle fully, I feel engine does not accelate as good as if I close trottle a bit (approx 1/8-1/4).After ride I pulled plugs (I installed them new, 55 miles before), all cyls are lean. See attached pics. Good news are are equally lean (I have never achieved that before!)So, rising needle 1-2 notch looks to be next step..