Engine parts assembly for three wheelers, gathering the moving and wearing parts of the engine in one set. It includes a finned cylinder barrel with piston, a connecting rod, a crankshaft, circlips, bearing shells and bushes, rocker arms, a small gear, push rods and long studs. These parts turn the piston's up and down movement into the crankshaft rotation that drives the vehicle, and are the ones replaced when an engine is rebuilt.