One of the problems with a 30 year old bike is having 30 year old rubber and plastic pieces.  These pieces eventually dry out, becoming brittle, and break.  Sometimes these parts are small, like the starter button.  Note the hole just below the yellow word “START” on the right, to the left of the grip.  This is where a black plastic button about the same size as the hole should be.  After 30 years it broke one day when I pushed it.  So I had a friendly session with the handle & found out a) there’s a reason it is an insulated button, an uninsulated metal button will blow the main fuse, b) you can shock yourself if starting your bike with a key (by inserting it into the hole) while not wearing gloves.  Sometimes hard to find part, occasionally can be found on ebay for about $8.