Jet Mikuni 42mm CarburetorPart Number CKC-86
Jet for Mikuni HSR 42mm carburetor.
The beauty of the Mikuni Carb is it's easy tuning capability. In 5 minutes you can change the jet to adjust air fuel ratio.
after you install your carb, or anytime you add other modifications you will need to check your spark plugs for color. White means too lean, increase jet size, black means too rich, decrease jet size. You want the color to be a tan, light coffee color.