Honda VT750C2B Owner's Manual page 203

Emission Control Systems
Exhaust Emission Control System
The exhaust emission control system
includes a secondary air injection system,
an ignition timing control system, a
PGM-FI system and two oxidation
catalytic converters.
No adjustment to these systems should be
made although periodic inspection of the
components is recommended.
196
Technical Information
Programmed Fuel Injection (PGM-FI)
System
The PGM-FI system has four subsystems:
Air Intake, Engine Control, Fuel Control,
and Exhaust Control.
The Engine Control Module (ECM) uses
various sensors to determine how much air
is going into the engine. It then controls
how much fuel is injected under all
operating conditions.
Ignition Timing Control System
The system constantly adjusts the ignition
timing, reducing the amount of HC, CO
and NOx produced.