My 2009 Nighster is having troubles. The neutral light works fine when cold, however once fully warmed up if you turn off and back on light doesn't work and it will not start nothing not even a click. All other electrics work . Let it cool light comes on and it runs fine??

 

check and see if it is making good connection at the plug it maybe has some corosion at the plug. It is located on top of the tranny. It might have to have a complete circut for it to start. Get the bike warm as you said and shut it off and wiggle the plug and see if light comes on and starts.Put some dielectric grease on the plug

 

Will try that mate, cheers. It's driving me mad had thought it may be neutral switch but it should start with clutch lever engaged then surely?