Motorcycle Repair: starting, yamaha seca 400, starter systems

Question
I have a 1982 yamaha seca 400 that has been sitting for about a year. It ran
great before sitting but now will not start with the button. I can put power
straight to the starter or to the solenoid and it will start, but the button will
not work.
There are four wires going to the starter button, and two of them have power.
when I push the button one of those wires looses power. The blue/white wire
that goes from the start button to the solenoid never gets power.
Any idea what could be the problem here? Please let me know if there is any
more info you need. Thanks for your help!

Answer
Brian,

-The starter systems vary a bit between
different years and models of all bikes.

-On your bike I believe the starter works
on a grounding method to engage the solenoid.

-You are correct in your assessment of the
wires for the most part.

-The blue wire should lose power when you
press the start button, this is to temporarily
disable the headlight to supply more starting current.

-the black wire is your ground wire.

-the brown wire is the power wire for the headlight
system.

-the blue/white wire goes to the solenoid BUT
it is NOT a powered wire, it works on the ground
side of the system. In other words, when you
push your starter button, it grounds the
wire to the solenoid to make the bike start.

-in order for this to work the solenoid red/white
wire has to have power and sometimes it gets
it through a complicated relay which is
connected to the side stand and clutch switches.

-so it may not be your button at fault,
get some power to the solenoid red/white
wire. Then try grounding the blue/white wire to start.

-check your fuses, clutch and side stand switches, grounds.