You can rent anything, from bicycle to Ferrari but there are few tips:
1. When you rent any type of vehicle (but especially motorbike) never leave passport or any other ID document as deposit. It’s normal to leave copy of the passport.
2. There are no wide spread vehicle steals in Pattaya but sometimes they happen. Best way to avoid it not to leave your transport outside the inhabited area or poorly lighted places.
3. Good idea to buy your own vehicle lock in case you’ve rented motorbike. One you would be given by the owner, but keep in mind that second key will stay with him. Sometimes, if you rent motorbike not far from your place, owner can move motorbike to another parking while you’re sleeping for example. I this case he would try to keep deposit and charge money for the motorbike loss.