Side-valve four-stroke engine

This is a unit engine with the camshaft positioned at the bottom.

Functions:

Turn the star handle (crankshaft), the piston moves up and down
The camshaft at the bottom is driven and opens the valves
Intake, compression, working and ejection
Function of the magnetic ignition with interrupter or breakerless
Starting of the engine via manual starter
Function of air filter, carburettor (with floater and throttle valve), exhaust silencer, fuel tank, fuel tap, oil tank, crankcase ventilation
On the camshaft, there is a centrifugal advance device, which turns the throttle valve in the carburettor via a linkage, in order to regulate the speed.