I have had this scooter for a few years. Was a gift. Rode fine. Last year the starting became a bit of a problem. It gradually got worse until finally not starting two weeks ago. I checked the battery, checked the wiring, replaced the Carburetor and it still will not start. I made a video.
The problem is in the Bendix drive not engaging the starter gear with the variator gear. The wires and starter must be good, and provide good current to the starter motor so it will turn the armature fast enough to engage the Bendix. Take the CVT cover off, and see the tip of the Bendix hanging free above the variator. You can pull the Bendix out, (wiggle back and forth, and it will come), and inspect that it move freely. If stuck, you may free it up with some light lube/cleaner like WD-40. It MUST move freely as its inertia is what makes it move out and engage the gears. You can just replace it if you want. If your battery, cables, relay and starter are good, replacing the Bendix will make it crank again. Adjusting the valves may be something to consider in the future. You can check the clearance if you want and have never done so. A metric feeler gauge or inch will work. Get the cam sprocket with the big hole at the top, and the two small holes parallel to the cylinder head cover gasket surface. Measure between the rocker tip and the valve stem. About .004" will do for both, though exact specs are different. That clearance will get you running, but may be a bit 'tappy'. tom