@agentparas, have a try at some shop close to you which fits your handsize most.
Think you mean the grip cover made from foam or another stuff? Or you want to change the gas assy?
Too big and too soft makes handling squirmy.
Kymcos do NOT vibrate that much as other brands
RH grip cover is always a few mm wider in inner diameter than the left one.
-chose the one you like
-cut the old ones off
- push the new on (with water as lubricant only)
New ones of good quality fit tight without any glue applied.