Boyer, 1980 mfg. date. I strobe timed it, it felt numb, Dyno dave heard me ride across his yard, "sounds retarded"...
"I know"
So, I bumped it up a couple degress until it pulled and sounded good, yet no audible pinging.
The half dozen times I got shit gas sold as Premium, it would audibly protest 1/2 to 1 mile from the pump. I'd try to go easy, not ask much of it, free rev rather than lug, and dilute with (another attempt) at good fuel after 30-50 miles.
There were heavy combustion chamber deposits, so compression could have been a bit up.