I have the same issue I have 3 car batteries and 3 bike batteries as well as a new battery in the vxr200 scooter.
No matter what battery I use all I hear is the starter relay on the rh tail section click when I press the starter button. No voltage seems to reach the starter motor.
Also, directly powering the stater it only throws out the starter bendix gear, as soon as it mates with the crank ring gear it won't turn the engine over.
The engine is not seized and I have even tried a new starter bendix assy in thinking it may not be meshing.
So my issues
Power to starter motor
If power does feed the starter it only engages the bendix it won't turn the engine over as if the engine is seized BUT ITS not it turns over freely without the s plug in by hand off the ring gear when I removed the drive train casing.
Atm it's getting power to the starter that's my main concern I'm sure the other issue may be a weak starter motor.