Thanks Ant, that's the sort of feedback I was hoping to get.
I have disconnected the powerizer, and now the bike seems to be stuttering much less even when cold. Nonetheless, it seems to have some strange behavior in first gear, where delivery really isn't as smooth as you'd expect... it accelerates and then has some power gaps until 4k rpm, when it picks up again. But if I throttle more smoothly, then no problem

you are welcome - i am relatively new to buells myself - there are many on here who know better than i.

bought a poweriser myself but on tubbs' advice sold it on via ebay without fitting it.

once its warm there really should be no obvious holes in the power delivery. i recently changed ECUs to put the EBR race unit on and it was horrible and lumpy - almost unridable when cold - until the TPS was reset and then absolutely fine afterwards - and i prefer the power delivery now - seems somehow slightly more eager to go if not especially ultimately quicker.

i never run the thing flat out anyway - thats not what this motor is all about.

hi david
welcome i don't know whats going on with my powerizer cus it works just fine it smoothed everything out nice but it seems im the only one.sorry thats of no help to ya just thought i would drop that in happy buelling