Legal and technical term for motorcycles with an engine displacement of 50cc or larger, as defined under Japanese vehicle classification. In everyday speech, バイク is more common.
To get a motorcycle license, you need to attend a driving school.
This parking lot is for motorcycles only.
Common everyday word for motorcycle, regardless of engine size. 自動二輪 is a formal legal term.
Legal term for mopeds and scooters under 50cc, often called 原付 (げんつき).
Compound of 自動 (じどう, 'automatic') and 二輪 (にりん, 'two wheels'), literally 'automatic two-wheeler'.