srf slide bi replace ho jathi ha,, normally it is just replaced,,without looking at its condition i cant say exatly what to do,,
i m sure a total replacement is noit needed,, however if it is needed then check ur pocket ,,aftermarket will perform as well a janyeen,, if u can afford it buy genuine ,,but ajkal 2 number k janyan kah ka baichtha hainn,,
i have very bad experience with lifan,,
aftermarket are not as good and durable as genuine,,,
and if u go for aftermarket buy taiwanese one ,, which has good float ,,the metel strip connecting the two float balls and onto which the valve spring hangs should be of steel as is in original,,lifans is of brass and very poor quality brass,,