Rayborn grew up in San Diego during the ‘50s, when that city was a motorcycle-racing hotbed. His stepfather was a motorcycle racer who taught him to ride, and “Sluggo,” as he was known to friends, honed his skills working as a motorcycle courier. In that job, each second saved put more money in his pocket—essential motovation. Rayborn’s first “racebike” was a pedestrian Harley-Davidson Model 165. “It was hardly a racer,” remembers his friend, Jim McMurren. “It was old, and the tires were so worn-out their profile was flat.” But Rayborn’s mentor, Lou Kaiser, had tuned the tiny, 165cc two-stroke with a reed valve and it was actually pretty fast. “Man, we laughed when Calvin brought that little Harley out to Hourglass Field, an abandoned WWII training airstrip where we used to race,” McMurren recalls. “We laughed and laughed right up until Calvin beat our asses with it, winning his very first race.”
These photos from the 1962 Cajon Speedway program are the only known images of Rayborn rid
Rayborn soon became a feared roadracing competitor at Hourglass, Riverside, and pop-up road courses like the one at Paradise Mesa drag strip. Next he took up TT racing at famed venues like Ascot, Gardena and his home track Cajon Speedway, where he raced alongside regulars like Eddie Mulder, Malcom Smith, and Don Vesco. “Everyone hated racing Cal,” remembers another friend, Gordon Menzie. “The way he could scrub off speed using just the front wheel was unbelievable. You did not want to enter a corner alongside Cal, because he was going to beat you every time. He didn’t know how to lift.”
Rayborn rode whatever he could get his hands on in those early days—BSAs, Triumphs, even the very first Yamaha in America, the same two-stroke twin Fumio Ito raced at the 1958 Catalina GP. He was never afraid to ask for a ride. “One night at El Cajon this older guy named Grant Brown showed up with a brand-new BSA Spitfire,” McMurren remembers. “He was really going to show us how TT was done. Anyway, he missed a gear going into the first corner and crashed into the fence. They were loading poor Grant into the ambulance and there was Calvin running alongside: ‘Grant! Grant! Can I ride your motorcycle, Grant?’ Brown said, ‘You can have the sunovabitch!’ Calvin rode it, and of course he won.”
The CSR was soon nicknamed “The Golden Eagle,” due to its telltale, gold-painted magnesium engine cases. It made a better desert racer than a TT bike.
Soon, Rayborn didn’t have to ask. His first real sponsor was an eccentric San Diego motorcycle dealer named Saylor Main, who became famous for taking surfboards on trade for Honda Super Cub scooters at Sun Fun Sports, his beachside shop. Main gave Rayborn a Honda CB72 Hawk that he converted for TT racing. He immediately began winning races with that Hawk, especially at El Cajon, a short track that favored the fine-handling little Honda. While the 250cc Hawk excelled in the lightweight class, Rayborn needed something bigger for the open class—which is where #286 enters the picture.
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The custom primary cover was made by Rayborn and his friends, to simply service. They trie
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The bike is fit with a single-shoe drum front brake, but Rayborn reportedly rarely used it
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Look closely and you’ll see that the rear hub was swiss-cheesed with massive cutouts to sa
Sun Fun Sports was also a Matchless franchise, and it had received one of the 25 CSRs built for AMA homologation. The AMA’s archaic Class C rule structure, which dated back to the depression, prohibited purpose-built (read: expensive) factory racers like the G50 from competition. As a result, there were just a handful of genuine G50s ever imported to the States, including a small fleet owned by Bob Hansen, then American Honda’s national service manager, who mostly raced in Canada, and another that belonged to Don Vesco, by then one of Rayborn’s closest friends, who rode his G50 at regional AFM events.
The CSR (Competition, Sprung, Roadster) was created by combining the G80CS scrambler chassis with the SOHC G50 engine (replacing the G80’s pushrod powerplant), and then adding a generator, lights, and a muffler for street-legal status. Rayborn and his friends did their best to prepare the CSR for TT racing, but by all accounts, it was unfit for this purpose. “You can just look at it and see it’s not a great TT bike,” McMurren says. “The CS chassis was intended for scrambles, or desert racing. The forks were way too long and it was quite heavy—I bet it weighed over 400 pounds. It didn’t handle worth a crap.” Actually, it was 360 lbs. wet.