As nearly an expert in all things roadways these days thanks to the venerable Kanagawa 5-0 Driver's License Dante's 7 Rings of Hell Testing Sadism...
1) Mopeds and bicycles may travel on the side strip or to the left of car. This means motor scooters 50cc or under, btw. So - 'undertaking' cars on the left is ok.
2) What's kind of messed up with this , though, is a car , may double overtake you! Meaning, if you are overtaking a vehicle in front, the car may legally overtake you AND the vehicle in front of you. It's pretty much like you (cyclist) don't really exist.
3) Rules between vehicles. The larger vehicle (motor, class, size) shall ALWAYS give way to the smaller in the case of determining priority.
4) So, if you hit a 50cc scooter with your bike, the fault would be at least equally distributed with priority given to you.
Case Study - Quite a few years ago I was riding home on my Honda Cub (50cc). A cyclist bunny hopped off a kerb directly in front of me. I laid the scooter down to avoid striking the bike, but I did hit the rear wheel and it caused the rider to stumble slightly and he had a slow speed tip over. Even though the cyclist was at fault for not looking before he entered the roadway (even confirmed by himself in the statement), I was held largely at fault and had to compensate him. (essentially apology money). He only had to provide me a written apology, even those his idiocy caused me to lay down my Cub and scratch the fairing, etc.
Case Study - Like you I was going home on my bike (pedal type). At a construction zone I was squeezed off from the right by traffic into a dump truck pulling out. I smacked the dump truck's mirror with my shoulder. The driver yelled out and a red stick guard stopped me. The driver wanted me to compensate him for damages to his mirror. There were no damages that anyone could see - I mean, I just smacked it with my shoulder and knocked it out of alignment. So, I suggested he call the police. The Police came and heard our stories. He told the truck driver to be more careful of small vehicles. And he told me he was sorry that I was put into a dangerous position. The traffic guard should have been more conscientious.
In almost every case that I've been in or heard of - the result is the same. Fault lies with the larger and more powerful vehicle. Not 100%, but generally speaking. This is why, also, at the driver's testing, you will fail immediately if you show ANY lack of caution at ANY intersection or fail to properly 'pinch the kerb' in left turns to prevent cyclists, scooters and pedestrians from 'accidentally' coming between you and the kerb.