When Jim drives Rocky's truck through the bikers at the picnic and stops the truck to pick up Coop, the truck's tires squeal as if they were on pavement instead of dirt.
Jim Rockford is a pretty street savvy guy that excels at avoiding confrontation. It's out of character in this episode #5.18 for him to honk at a ton of bikers. He also isn't normally dumb enough to block them in a truck and get out of it to confront them with a pipe, although he was trying to rescue Coop's sister Gail. Still a good episode.
Though most of the signs at the gas station were covered with the name "Pro-Tec" some "Chevron" signs were seen.
Although all the gang's motorcycles were Harleys. camera view as a rider shows the tachometer and handlebars of a Honda CB 750-Four.