06 Predator 500 Start button don't work battery won't charge
 

I replaced left handlebar start/kill/headlight control and neutral brake start diode and the start button still doesn't work. I can get it fired up by jumping the solenoid and when I put my volt meter on the battery it stays at 12 volts flat. I also have to force it to stay running with the throttle engaged. As soon as I let off the throttle it dies. Any help would be extremely appreciated. Thank you