Nozzle size determined by flow rate!
This is the part that no two-stroke off-roader should skimp on! If your carburettor is not adjusted correctly with a slightly smaller nozzle, in a slightly colder weather you can be richer with a broken cylinder!
Only with the factory-calibrated nozzle is it guaranteed that you will always set your engine as precisely as possible. Compared to nozzles sized based on the hole diameter, you can adjust your engine about 10x more precisely. It is not possible to work accurately with hand reamed nozzles, just once, the next nozzle will be different, even if you measure the most accurately.
Main dimensions of the nozzle:
Hexagon size: 6 mm
Thread: M5.3 x 0.9
Total length: 11.5 mm
Thread length: 5 mm
Type: 4/042