Cylinder 1
INTAKE
Intake valve
open
Exhaust valve
closed
Spark
—
Firing order
1 – 3 – 4 – 2
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Course complete!
Fuel + air burn → pressure → pushes the piston.
Four strokes: intake, compression, power, exhaust = 2 crank turns.
Four cylinders fire 1‑3‑4‑2, one every half turn.
The crankshaft turns push into spin; the cams keep the valves in time.
Restart course
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