The following carburetor schematic diagram apply for Mikuni HSR42, 45 and 48 series. The HSR carburetor is divided into four interdependent systems:
1. Choke system
2. Idle system
3. Main system
4. Accelerator pump system
Each of these systems has its major effects in a different throttle range. While there may be some overlap, each system can generally be treated as though it is completely responsible for air/fuel mixtures within its range of throttle settings. Find more information about Mikuni HSR42|45|48 Carburetor Schematic Diagram here.