As recently as yesterday I read and responded to a question concerning starter wiring and the mysterious labels "S" & "R" for the terminals of the starter solenoid.
While motorcycling into manhattan this morning (in the rain) I had a flash of understanding:
The "S" terminal is the hook-up for the fat purple ignition switch lead, everyone agrees with this. But what does the "S" stand for? SOLENOID. This terminal activates the starter's solenoid.
The "R" terminal is hooked up to a yellow wire which leads to the coil, which supplies additional battery voltage to the coil ONLY WHEN THE STARTER IS TURNING. This is important, because it tells us what the label "R" means. The "R" terminal is a RELAY terminal, which is switched on and off by another circuit.
I haven't got documented evidence that these lables are correct, but they make a lot more logical sense than some of the other ideas that were floated in a previous post. And with this system of labeling one can actually remember what goes where and why.
Please, if I'm in err please let me know.
??michael j Team Chevelle Gold #77
70 Chevelle SS396 4sp, Fathom Blue/White Stripes - Canadian built