if it's a 100cc minarelli engine just like the aerox100 & bws100 then yes there's a cilinder kit available for it, check out malossi & polini 57,5mm cilinder kits but only Polini has produced an aluminum cilinder.
there are cheap taiwan made kits in 55 & 56mm sizes & there's a stroker crank available as well from FM which is taiwan made, i have the 51,5mm stroke but there's a 53mm crank but it's hard to get.