I've posted another video made from my old Super 8mm film collection. This one is of The Brush Barons' M/C "Carlsbad Grand Prix" in 1970.
The Brush Barons were the dirt bike racing club I belonged to back when if you wanted to race "official" sportsman races you had to belong to the American Motorcycle Association and also your local, AMA sanctioned racing club. Clubs back then had interesting names like "The Sod Busters M/C" or the "Los Ancianos M/C." The latter club was formed in 1960 and still exists.
In the late '60s and early '70s there were enough official dirt bike clubs in the San Diego area that between them all the could field a full year of off-road bike racing with each club putting on two races. We raced scrambles races and that new motocross thing in the summer and desert racing in the winter. Most of the old racing clubs in the San Diego area including the one to which I belonged have come and gone.
Racing was a smaller affair then, at least in the San Diego area. You knew people, knew their club by their racing jumper; their level of riding skill by the color of their number plate and the number on it. What you wore when you raced said something about where you fit into the club and your level of skill or experience, not just what garishly logo'ed jersey was on sale at your local "powersports store."
Each club normally had a distinctive color and patterned "jumper" to wear over your racing shirt so that you could be picked out from the pack during a race and when heading in for pit stops during a long desert race. There was an actual purpose in the design other than selling a product. The jumper in the photo above is mine from the Brush Barons. They were made by wives in the club, not a sweatshop in China. The colors were bright but not garishly so and there were no trite descriptors like "Monster," "Xtreme," "Insane," or "Madness." Everyone knew motorcycle racing was dangerous and slightly crazy, there was no need to point out the obvious with stupid graphics and ridiculous product names.

A little background on the race in the video: After the previous year's Elsinore Grand Prix some of my fellow club members thought that it would be possible and fun to host an Elsinore GP-style event at Carlsbad Raceway in Carlsbad, CA. Carlsbad was the home of the USA round of the FIM Motocross World Championship, also a well known 1/4 mile drag strip, and weekly motocross racing under the auspices of the CMC, an upstart sanctioning organization in those days. Someone in the Brush Barons had an in with the owner of Carlsbad Raceway so the details of using the facility were arranged. The only caveat was that we could not use the actual Carlsbad GP MX course as that was contracted to other people.

At the end of the day it was blazing hot and we were resting down by the drag strip. I was squatting down (my knees still worked in those days) and Steve Stevens proceeded to pour a cold beer into the gap at the back of my leathers. Not only was it cold but I went home smelling strongly of beer and had some 'splanin' to do to since I didn't drink. Come to think of it, that beer is probably why those leathers shrunk over the years and no longer fit me.
In due course the race was held and I think it was deemed a great success by the riders except for the guy who endo'ed right in front of me while transitioning from the dirt to the pavement. That was the moment that sold me on some sort of face protection for racing.
Carlsbad Raceway is gone now, over run by commercial development as is often the fate of great race tracks. I used to tell my wife that when I died I wanted my ashes spread on the Grand Prix motocross course at Carlsbad. I guess she'll have to find another spot for me now.
Anyway, here's the video. As always seems the case at interesting events I wound up holding the camera instead of the handlebars. The original 8mm film is dated July 1970.