Some of you remember me, because of some issues, of my bike. Well, after some serious lessons I managed to fix my beauty. Also put 2 new exhausts (handmade Greek

I'm starting to rebuilt my front, (ohlins springs) and the rear shock rebuilt.
But one problem remain:
---When I reach 3000 rpm and accelerate till 4100 rpm the engine knocks, like piston slapping, I dont know. Its coming from the engine I think th front cylinder.And I get noticeable vibrations.
The clutch also rattles, the noise when I disengage the clutch is similar, but it comes at the above range. It is the filter box? I'm afraid it's the coils because when it rains the front cyl dies sometimes and doesnt spark.
The performance is low as well.
K&N filter, Racetech echausts, Stock carb (i think)
PLEASE HELP!!