Hi Ung,
Nice one. The bike is an early 1920s P&M (Phelon and Moore), the forerunner to the famous "Panther".
In 1921 (or so) they tried a disastrous motor with fins parallel to the ground, so I suspect this one is 1922-23. Possibly with a 4-speed gearbox rather than the earlier 2-speed-primary-chain setup. Google will provide many photos for comparison.
The bike was a few years old by 1930, which explains the non-standard paint scheme.
Cheers
Leon