Mikuni Low-Speed Jet Set, Size 15-37.5.
M4.8 thread; check the thread.
4.8 mm measured across the thread, 0.8 mm pitch.
The M4.8 low-speed jet is also available for carburetors that use an M5.2 main jet.
These may be discolored from the factory, but they function properly.
Sizes: 13.5 / 15 / 17.5 / 20 / 22.5 / 25 / 27.5 / 30 / 32.5 / 37.5