There are about 150 motorbike accidents a day in Denpasar that require a visit to the emergency room, so there are probably 2 or 3 times that number which go unreported. We try to be really careful and thankfully haven't had any serious problems. We've had two small incidents in our 3 years here, one of which happened two days ago...
I was heading to the office and passing a bus. The bus decided to swerve over towards me, I braked while turning slightly to the left. All of this is fine except for the presence of a big patch of sand under me. I lost traction and had to come off the bike just a bit to keep from really taking a spill. No problems except for a sore hip...