This is too simple and somewhat wrong. First, the spark timing is set by the crankshaft. The plug fires a few degrees before TDC on both the compression and exhaust stroke. There is no adjustment for the spark timing therefore the manual only describes how to check it! Spark advance is controlled by the CDI box.
The cam timing is critical, but should not change during operation, except for slight retarding caused by cam chain wear.
When checking cam timing, always have the engine at TDC of the compression stroke (the cam lobes will be pointing down). Refer to the service manual to do it right.
Hard starting might be a compression problem (check valve adjustment), an ignition problem or a carb problem. Most hard starting is compression or fuel related. With the throttle held wide open, the compression should be about 120 to 150psi. If the compression is good, how is the fuel? Is it fresh? A month old is severely degraded. Use 92 to 95 octane. With all this OK, check the spark. Use a new plug and close the gap down to about 15 thousandths. If it starts better, you might have a spark plug cap, coil or stator problem.
Cutting out unless floored? Sounds like it might be rich at idle. When floored it leans out. Check to see that the idle jet is the correct size and that the fuel mixture hasn't been screwed with. Simply setting the fuel mixture screw could solve all your problems.
Good luck
