I would check the battery first. May have enough to turn but not enough to give the system the juice it needs.
An easy bypass - jump the scooter with a car to guarantee that it spins FAST and HARD. I've owned my 2005 GV250 since 2011 and went from 2600 mi to 20K. When the battery gets "soft" the scoot will have trouble starting.
So you need to ...
1. Turn the key on, and press the brake lever - THE BRAKE LIGHT MUST COME ON AND STAY ON or the engine will NOT get a spark.
2. Kickstand / Sidestand must be up if it is down the motor will still turn over but it will NOT start.
3. You need GAS! If the scooter has sat or is being "resurrected" buy a can of starting fluid and pray the air filter - not the carb. If you Spray the air filter it provides "fuel" to allow the engine to run for a few seconds.
4. If it still will not start you need to remove the spark plug - insert it back into the boot, lay it on the motor and crank the engine. You should see and hear a nice stream of sparks.
If "weak" spark verify that all wires are tight and in good shape. If no spark - verify that the brake light is coming on and side stand is up before replacing the coil or CDI & test for power at the coil - should be 12v continuous. No power at coil? check fuses.
COIL & CDI rarely go bad ever. Only coil I have ever seen go "bad" on a motorcycle was due to age - 18 years old and developed fine cracks in the plastic which caused the spark to arc to the frame.
