I'm not sure this is repaired as such, mostly I wanted to fill the hole to stop water and muck ingress. It's the throttle cover plate from a Yamaha DT200. There's no markings to indicate what type of plastic it is. I used powdered acrylic and solvent, it's normal use is for for fake fingernails.
A small test as I'd not done this before:
The hole, taped to an old wood chisel. I wanted a rigid, smooth flat surface that wouldn't damaged by the solvent:
Filled with a suitable amount of powder, plus a allowance for the airspaces in the powder:
Solvent added and mixed with a dental pick:
