Pinking problem... Please help!!!

[stonerosesmod]

Hello all you good people!
Ive got a PX125 disc and im 80% through running in a Punjabi 150cc top end.The other spec is,

PX200 24/24 Carb
108 main jet
Hole drilled in air filter above main and idler jet
Simonini exhaust
Pre-mixing (adding slightly more oil during running in)
Shell optimax used
BP8ES spark plug
Timing slightly retarded.

Ive ran it steadily so far for 250 miles at 40mph with no bother,but now im another 150 miles or so further on,when i get to around 45 or have to accellerate slightly the top end will pink like mad.This happens when the revs get highish also.

Ive tried going for a 106 main jet to a 108 and back and have altered the timing from standard to advanced slightly,and back through to fully retarded (this runs smoothest) but still the pinking is still there and is doing my nut in!
The plug is a chocolate brown/sooty colour.

P.S it also takes 8+ kicks when cold evertime to start it,but starts first kick evertime when warm!

Can anyone offer any advice or is there another help forum i could try?

Thanks!

[Smallframe]

have you set the squish on cylinder head correctly?

[bryno]

Out of interest mate, why have you drilled a couple of holes in the airfilter, was it a trick recommended by a tuner?