What displacement motorcycles are allowed on highways?

[Barbosa]

Motorcycles with an engine displacement of 50cc or above are permitted on highways. Below is relevant information about motorcycles: 1. Basic components: A motorcycle consists of five main parts - the engine, transmission system, running gear, steering and braking systems, and electrical instrumentation. 2. Working principle: Four-stroke engines are widely used. In a four-stroke engine, the piston completes four reciprocating movements for each ignition in the cylinder. During this process: The intake valve opens while the piston moves downward, drawing the air-fuel mixture into the cylinder. Both intake and exhaust valves close as the piston moves upward, compressing the mixture. When the mixture reaches maximum compression, the spark plug ignites it, and the resulting combustion pressure drives the piston downward, rotating the crankshaft.