Been there with my Classic. Took me 12 months to get the thing running right.
You say wet plugs/pistons but you have a spark - sounds like you have a bit of an injection problem. Would suggest substituting the ECU first, or at least disconnecting it and giving it a reset.
Make sure your battery is well charged.
Check all the wiring on injection and ignition circuits, make sure the connections are clean and dry. Undo, clean and re-make all your main earth connections. Get out your DVM and check the various sensor inputs into the ECU, there's lots of info on that - do a search.
BTW you didn't say which injection system you have.
You could try disconnecting the air flow meter and seeing if that makes any difference - it did on mine and highlighted a duff ECU which went undetected.
it turned out to be the plugs after taking them all out one at a time and trying them only one was actually firing new set of plugs and away we go good job really its taken me years to convince her indoors to have discovery