wˈʌn ʌvðə mˈoʊst pˈɑːpjʊlɚɹ ɪz ɐ bˈeɪs fˈɪfti ˈɛndʒɪn, ɐ dʒənˈɛɹɪk tˈɜːm fɔːɹ ɪmpˈoːɹɾᵻd sˈɪŋɡəl sˈɪlɪndɚ hˌɔːɹɪzˈɔntəl fˈɪfti sˌiːsˈiː tə wˈʌnhˈʌndɹɪd fˈoːɹɾi sˌiːsˈiː fˈoːɹstɹˈoʊk ˈɛndʒɪnz dᵻɹˈaɪvd fɹʌm hˈɑːndəz lˈaɪn ʌv smˈɔːl mˈoʊɾɚsˌaɪkəl ˈɛndʒɪnz.
One of the most popular is a Base 50 engine, a generic term for Imported single cylinder horizontal 50cc to 140cc 4-stroke engines derived from Honda's line of small motorcycle engines.