i am trying simoniz grey plastic primer on motorbike plasics how long before overpainting ,,and is this simoniz product any good , was also thinking about tetrosyl .hard to know which is good tbh
"Motorbike plastics" could be anything from ABS to polypropylene. They should ALL have a little logo printed on them somewhere telling you what the plastic is. Find that then Google the appropriate paint/primer for the part. There will be a plastic specific coating which will be different for each different type.