English version comes after Japanese.
日本だと「バイク」ってエンジン付き二輪車のことですが、英語で「bike」と言った場合、「自転車」と理解されることが多いので「Motorbike」か「Motorcycle」と言ったほうがいいです。ちなみに「Bicycle」という単語は「２」を表す「Bi」と「車輪」の意味の「cycle」に分解できます。
Japanese people usually call a motorcycle a "bike". According to Wiki, it originally came from an American English "auto-bike" and then we shortened to "auto-bi" when a magazine "auto-bi" was published. Afterwards it was changed again to "bike" when young people found "auto-bi" not cool.