Busar ta ƙunshi sassa shida masu zuwa: injin, matatar iska, jikin busarwa, ɗakin iska, tushe (da tankin mai), bututun digo. Busarwa ta dogara ne akan aikin da ba a saba gani ba na rotor mai son zuciya a cikin silinda, kuma canjin girma tsakanin ruwan wukake a cikin ramin rotor zai tsotse, ya matse kuma ya tofa iska. A yayin aiki, ana amfani da bambancin matsin lamba na busarwa don aika man shafawa ta atomatik zuwa bututun digo, ya digo cikin silinda don rage gogayya da hayaniya, yayin da ake ajiye iskar a cikin silinda baya dawowa, irin waɗannan busarwa ana kuma kiransu busarwa mai zamewa-vane
