Join Date: Sep 2008
Location: Honolulu, HI, USA
Just been through this on my '85.
You need to remove the switch assembly from the right bar and clean it.
It's held on with a small phillips head machine screw that runs forward and horizontally. That screw can be tight so be sure your screwdriver is up to snuff. You may have to remove the large phillips that secures the cover next to the brake fluid reservoir, just above the switch assembly (I had to).
The pushbutton is retained from the bottom by a c-clip. Slide that off with something pointy but be sure you can catch the button when it falls out, the brass contact and most importantly there are two tiny springs, less than 1/8 inch long. Don't lose them...
Once the brass contact is out, burnish all visible brass clean and shiny. The starter is activated when the brass contacts on the button hit the protruding brass contacts that are opposite each other... you'll see how it works when it's apart.
Once again DO NOT LOSE THE TINY TINY SPRINGS, they are essential for the kill switch to work properly.
If you get this far I don't have to tell you how it goes back together.