Motorcycle Questions? Ask a Mechanic.
Okay, if you're confident the battery and cables are good and all connections are tight then the next step is to make a jumper wire out of a heavy gauge wire (12 or larger). Remove the green wire from the starter solenoid terminal and, with the bike in neutral, connect the jumper wire from the positive battery terminal or large lug on the starter solenoid to the small solenoid terminal. This will bypass everything on the bike and tell you whether the high amperage starter circuit and solenoid is working properly.
Do this and let me know what happens. If the starter turns the engine over normally by doing this you'll need a voltmeter and be prepared to do some disassembly in order to do further troubleshooting.
Let me know what you find. Thanks, P.J.