I have this problem, when the bike is warm, it won't start. You added a wire from battery to starter solenoid?
At first that's what I thought cause I got it at walmart, so I went to cycle gear and got the oem replacement, no go, then I upgraded to the heavy duty
Dropping to 6 or 7 volts while starting ? There's a battery problem there. Maybe yur battery is to small? Not enough cranking amps?
It is a new battery! Lol, I've replaced it 4 times already. Properly charged, checked rectifier, I'm stuck