Yes, small motorcycles can have four cylinders. The number of cylinders in a motorcycle engine is not limited to the size of the bike. While smaller motorcycles typically have single-cylinder or twin-cylinder engines for reasons of cost, simplicity, and weight, there are exceptions.
Some manufacturers produce small motorcycles with four-cylinder engines to provide higher performance and a smoother power delivery. These motorcycles are often sport-oriented and designed for riders who prioritize speed and acceleration. Four-cylinder engines can deliver more power compared to single-cylinder or twin-cylinder engines, but they are usually found in larger bikes.
In the context of motorcycles, small typically refers to engine displacements ranging from 125cc to 500cc. While it's less common to find four-cylinder engines in motorcycles within this displacement range, it's not impossible, and there have been instances where manufacturers have produced small motorcycles with four-cylinder engines.