85 zn1100 headlight issues

Hey all,
 have a strange issues that’s popped up , when the bike is running and the clutch lever is pulled in the head light turns off , out of curiosity i bypassed the clutch switch and head light stays on . Now the neutral switch is causing the head light to turn off when the bike is put in first gear anyone come across anything like this?  Another issue which may be contributing to this is starting issue , I’m not getting a consistent 12v to the starter solenoid to activate it , one button push will be 3 volts next will be 1 and so on , every 10-15 pushes I’ll get 11-12v and the solenoid will activate . When it’s not getting enough voltage the round silver relay in the junction box just buzzes . Replaced all relax and the entire junction box with a known good one , replaced the reserve lighting as well .  Kind of at a loss any info would be appreciated 

Hey everyone ,
 after replacing every components and testing plenty of wires I figured it out .  It was the starter button all along , after being in there and looking a few times I tried again and discovered the button was a 1/16 of an inch away from making full contact on the pin inside , this was causing my erratic voltage to the solenoid .  Does anyone know a place to source a new pin and spring for inside the right hand controls? I’ve shimmed between the button and the pin right now it’ll work but I’d like to fix it correctly thanks 

replacement starter button. Z1Enterprises. assuming it will work for your motorcycle. www.z1enterprises.com/yamaha-xs650-butto...-oem-27010-1009.html ... in the description: Although not published, this is identical to the starter and/or horn button on MANY vintage motorcycles.