rattle noise with 172ac malossi on SR aprilia (with video)

hi everybody, i have a sr 150 with
172 malossi brand new (1200kms on it), it makes this orrible rattle noise at constant 1/3 1/2 throttle that disappear when i release or i give more gas. whit the original head don't do any kind of noise. the engine runs great, i checked everything it comes for sure from the cilinder but i don't know why. hope someone could help

can be heard at second 2 and at second 9 in the video

 

Raise the needle in carb, could be running lean ?

 

I put a aq268 insted of 266 and changed the needle with a d32 now the noise is disappeared, now i am rich at low gas, i wilm try to adjuat it with a 40valve, now i have a 30, so yes it was lean, did you heard it before?

 

I havn't watched the video, it's called "pinking" when it makes a rattling noise.