It takes three things to make an engine go. Spark, fuel and air. So perhaps something controlling each of those three things isn't working well. No way to guess here. Just start checking each of those. If you are mechanically inclined, I'd start the search by troubleshooting with the service manual. Page 13 of that manual is a very detail troubleshooting chart showing 27 repairs tied to "hard starting or can't start".
Print out that page on paper, take your time and go through each of the root causes. This is a great way to discover how things work, and the pride in fixing it yourself (Many of us have done this very thing... )
Is your vehicle fuel injected or does it have a carburetor? I see from the owner's manual for your scooter that both options have been produced. Look at page 15 of that manual. Is the Engine Management System (EMS) lamp present on your speedometer / cluster area? If so, you've got a fuel injected model. If not, then you have a carburetor.
Is that light on? If so, is it possible for you to get your hands on a code reader?
On other resource you might consider for this issue is http://www.modernbuddy.com/forum/ It's very possible the folks there may know quite a bit about your vehicle.
Good luck with it, stay safe.