Igice cyo hepfo ya silinderi aho crankshaft yashyizwemo yitwa crankcase. Ikariso igabanijwemo igice cyo hejuru hamwe n'ikariso yo hepfo. Crankcase yo hejuru hamwe na silinderi ikozwe nkumubiri umwe. Ikariso yo hepfo ikoreshwa mukubika amavuta yo gusiga no gufunga igikonjo cyo hejuru, bityo nanone yitwa isafuriya yamavuta. Isafuriya yamavuta ifite imbaraga nke cyane kandi muri rusange yashyizweho kashe kumasahani yoroheje. Imiterere yacyo iterwa nuburyo rusange bwa moteri nubushobozi bwa peteroli. Amavuta ahamye ya bffle ashyirwa mumasafuriya kugirango yirinde ihindagurika ryinshi murwego rwa peteroli iyo imodoka igenda. Hasi yisafuriya yamavuta nayo ifite icyuma gikuramo amavuta, mubisanzwe hashyirwaho magneti ahoraho mumashanyarazi kugirango yinjize ibyuma byamavuta mumavuta kandi bigabanya kwambara moteri. Igipapuro gishyirwa hagati yubuso buhuriweho hejuru no hepfo kugirango birinde amavuta.

Crankcase nigice cyingenzi cya moteri. Itwara imbaraga ziva mu nkoni ihuza kandi ikayihindura muri torque kugirango isohoke binyuze muri crankshaft kandi itwara ibindi bikoresho kuri moteri kugirango ikore. Crankshaft ikorerwa ibikorwa byahujwe ningufu za centrifugal ya misa izunguruka, ingufu za gazi zigihe cyingufu hamwe nimbaraga zidasubirwaho, kuburyo ibyuma bigoramye bikorerwa kunama no kwikorera imitwaro. Kubwibyo, igikonjo gisabwa kugira imbaraga zihagije no gukomera, kandi hejuru yikinyamakuru bigomba kuba birwanya kwambara, gukora kimwe, kandi bifite uburimbane bwiza.

Crankcase izashiraho ubuso bwo guhuza hagati yimpera nini yinkoni ihuza nikinyamakuru kubera amavuta yanduye n'imbaraga zingana ziki kinyamakuru. Niba amavuta arimo umwanda munini kandi ukomeye, hari n'ingaruka zo gushushanya hejuru yikinyamakuru. Niba kwambara bikabije, birashoboka ko bigira ingaruka kuburebure bwa piston hejuru no hepfo, kugabanya imikorere yaka, kandi mubisanzwe bigabanya ingufu ziva. Byongeye kandi, igikonjo gishobora nanone gutera gutwika hejuru yikinyamakuru kubera gusiga amavuta adahagije cyangwa amavuta yoroheje cyane, bishobora kugira ingaruka kumyitwarire ya piston mugihe gikomeye. Kubwibyo, amavuta yo gusiga amavuta akwiye agomba gukoreshwa kandi hagomba kubaho isuku yamavuta.