This are some bulletins regarding Sirio .12 engines.....hope it helps

AFM

Bulletin #1
When tuning your Sirio carb DO NOT adjust the mid-range needle. This is set from the factory on a flow meter to help calibrate the other two needles and should not be touched unless you really have a grasp on carburetor tuning. The mid-range needle can be found underneath the high-speed needle on the end of the carb opposite the low-speed needle.

Bulletin #3
Sirio .12 (General Base Carburetor Settings)
High Speed - 5.5 turns
Low Speed - 3-1/2 (Generally this should be flush with the end of the slide)
Mid Range - Flush then one turn out.

Bulletin #6
We recommend the use of the following plugs
- Sirio .12: (standard plug) Novarossi C7S or C8S
- Sirio .12 (turbo plug) Sirio S001720127

Bulletin #7
Crank pin on a new stock .12 engine has 4.428mm.
The right play between crank pin and conrod bushing is 0,04 - 0,05 mm. if you're not able to check it, I suggest you change the conrod every 2-3 hours running.
The life of the conrod depends mainly on the fuel you use, as the lubrication and the right carburetion keeps your engine running well for long time.

Bulletin #8
This is the correct Break-In procedure for the Sirio S12 Evo2

1.- One (1) 125cc tank in the bench at WOT with very rich setting of HSN, avoiding it to go on 4 stroke.
COOL DOWN
2.- Three (3) tanks on the track at WOT on the main straight with very rich setting of HSN, as if the engine wants to die, and tuning the HSN at the end of third tank to get almost full power.
COOL DOWN AFTER EVERY TANK