Thanks guys, very good info.
I might be wrong, but for now I am pretty sure the solenoid itself is the problem. It always “clicks” when I push the button, but only seems to connect the starting circuit now and then. The voltage to the battery is normal when the bike is running, and the battery itself has good power. The starter motor turns strongly when it reacts at all. It works well or not at all if you know what I mean.
I did order a solenoid today, I should get it in a few days.
Thanks again, it is always really helpful to get some input from you guys.
Yamaha XT600E '01, Honda XR400 '03, Yamaha XT550 '83