Definition: Motorcycle

Category: Transport

Two-, three- or four-wheeled road motor vehicle not exceeding 400 kg (900 lb) of unladen weight. All such vehicles with a cylinder capacity of 50 cc or over are included, as are those under 50 cc which do not meet the definition of moped.
(Fourth version of the Transport Glossary)

Two-wheeled road motor vehicle with or without side-car, including motor scooter, or three-wheeled road motor vehicle not exceeding 400 kg (900 lb) unladen weight. All such vehicles with a cylinder capacity of 50 cc or over are included, as are those under 50 cc which do not meet the definition of moped.
(Third version of the Transport Glossary) http://ec.europa.eu/eurostat/ramon/other_documents/transport_glossary_4_ed/index.cfm?TargetUrl=DSP_TRANSPORT_GLOSSARY_4_ED Eurostat, ECMT, UN/ECE, "Glossary for Transport Statistics", 3rd Edition, Luxembourg 2003