If you are not legally riding a motorbike it is very unlikely you'll be able to make a successful claim. What does "legally" mean - depends on the country. Vietnam, for example, requires you to have a valid Vietnamese driving license to legally ride a motorbike. The test needs to be booked a month ahead and it's in Vietnamese.
EU countries will accept a valid motorcycle rider's licence from any other EU country.
Many countries (most in fact) will accept an International Driver's Permit - which is a document stating you are licensed to drive certain classes of vehicle at home, and that'll do for the country you're visiting. But you need to be licensed to ride a motorcycle in your home country for that to show up on the permit (ie you can't magically upgrade your license).
So if you are a legally licensed motorcycle rider in your home country, get an International Driver's permit as step one. Step two is to check the local laws: do they accept the IDP, is there a supplementary test, etc. Generally, to be insured for motorbikes you have to be operating it within the law of the country you're visiting.
Have a look at a piece I rote about motorbikes in SE Asia:
http://journals.worldnomads.com/safetyhub/story/62697/Worldwide/Do-I-Need-A-License-To-Ride-A-Motorbike-In almost 10 years ago