what i am counting price of rebuild engine will be nearly half price of bike what i paid when i bought it buy other engine is always risk. if you dont know engine and if engine is out from bike its problem try it (start) and check compression and check oil use or transmission. and price of used engine is same as rebuilding engine or half price of used bike. that means i prefer to do it my self i know what and how is done. hope you understand what i mean. sorry for my english.