Ready to Race: 1960 Yamaha YDS1 Scrambler
1960 Yamaha YDS 1 Scrambler
Engine: 246cc air-cooled OHV 2-stroke parallel twin, 56mm x 50mm bore and stroke, 8:1 compression ratio, 20hp @ 7,500rpm (claimed)
Top speed: N/A
Carburetion: Two 20mm Mikuni VM 20
Transmission: 5-speed, chain final drive
Electrics: 12v, flywheel magneto ignition
Frame/wheelbase: Dual downtube steel cradle/50.7in (1,288mm)
Suspension: Telescopic fork front, dual shocks w/adjustable preload rear
Brakes: 7in SLS drums front and rear
Tires: 3 x 19in front, 3.25 x 18in rear
Weight (dry): 291lb (132kg)
Seat height: 30.75in (781mm)
Fuel capacity/MPG: 4.09gal (15.5ltr)/71mpg
Price then: $649 west coast; $659 east coast (1960)
Today the name Yamaha is synonymous with racing.
Yamaha Motor Corporation was originally created in 1955 as a repurposed company from long-standing Nippon Gakki, a conglomerate with roots dating back to 1889 when Torakusu Yamaha formed the musical company Yamaha Organ Manufacturing; thus the famous tuning fork logo. The new motor company’s mission was to develop and manufacture motorcycles.
Fittingly, Yamaha’s race history begins with the very first Yamaha, the YA1, launched in May 1955 and powered by a nondescript 125cc 2-stroke engine based on DKW’s RT 125 piston-port single. Two months after releasing the YA1 to dealers, Yamaha’s factory race team, itself still in the embryonic stage, entered a small squadron of the 125cc roadster for Japan’s most prestigious domestic race at the time, the Mt. Fuji Ascent Race. This marked the third year for the event that featured a one-way 24.2-kilometer (15.1 miles) course snaking its way partially up Mt. Fuji before reaching an altitude of 1,400 meters (4,600 feet) at the finish line. Racers were timed on the course to determine the winner; Japan’s fledging motorcycle industry paid close attention to who won — and who didn’t win.
Subsequently, Yamaha entries dominated the commercial bike division at Mt. Fuji in 1955, not only winning but crowding seven bikes among the top 10 finishers. Later that year a small armada of YA1 team bikes swept the top four spots at the inaugural closed-course Asama Highlands Race. Success breeds success and YA1 sales, having reached nearly 2,300 units for 1955, quadrupled the following year and nearly doubled again for 1957.
Yamaha has been racing its products ever since, especially in America, so perhaps now would be a proper time for us to pull into the pits to pause and pose the question: What is the most significant Yamaha production racer to ever take a checkered flag on America’s stage? A knee-jerk reaction by many U.S. race fans is to shine the light on the treacherous and oh-so-fast TZ750, a model that dominated road racing in America during the mid-to-late 1970s. The powerful TZ750 also helped launch perhaps the most enviable road racing career of any American — that of “King” Kenny Roberts. Not to be overlooked, too, is Yamaha’s early 250cc- and 350cc-based production road racers prior to the TZ750; just ask guys like Jody Nicholas, Ron Pierce, Don Emde, Gary Fisher and countless others who laid waste to the competition during their stellar road racing careers aboard Yamaha TD- and TR-based twins.
Or we might consider this bike, the 1960 YDS1 Scrambler. Even though it never won a notable championship — or even a major race — on these shores, the Scrambler qualifies as one of Yamaha’s first — if not the first — production racer available through Yamaha dealerships in America, taking its rightful place alongside another proddie racer of the time, a bike marketed as the Racer (a model that eventually assumed the name Ascot Scrambler, in reference to that legendary clay-packed oval race track where it dominated the Novice class during the early 1960s). Together these two Yamahas formed the vanguard for a legacy unmatched in U.S. competition today.
26 miles across the sea
The story of the YDS1 Scrambler actually kicks into high gear where, on the small resort island of Santa Catalina located 26 miles off California’s scenic coastline, it first raced in America. A little background about Santa Catalina: William Wrigley Jr., of chewing gum fame and who also possessed controlling interest in Major League Baseball’s hapless Chicago Cubs, also had been a major landholder of the island, and was responsible for much of the development that transformed Catalina into a resort destination. By 1952 Catalina’s commerce leaders, in hopes of persuading even more tourists to visit their bucolic isle, decided to promote a motorcycle race that looped through the town of Avalon before snaking into the surrounding hillsides. And thus was born the Catalina Grand Prix, a mainstay of racing on the West Coast until its final running in 1958 when, according to reports, a rogue group of rowdy bikers mugged one of the leading townsfolk, prompting the cancellation of future racing for good. The final GP also happened to be Yamaha’s first — and, of course, only — attempt at racing there. The factory entered five race-prepped versions of Yamaha’s new YD1, a 250cc twin that served as the company’s flagship model.
Some new parts had to be made from scratch, like the metal brackets holding the number plate.
Long story short, the YD1 originally joined the YA1 and YC1 (a 175cc model; a YB1 model also existed, but it was simply a slightly sportier variation of the YA1) in the lineup in April 1957. The YD1 was powered by the Tuning Fork company’s first 250cc twin-cylinder 2-stroke engine, and first order of business was to enter modified YD1s in a race, the 1957 Mount Asama Volcano Race (formerly the Asama Highlands Race, which was run in alternate years). Variations of the YD1 — two versions, reportedly designated as YD-A (its engine having a 54mm x 54mm bore and stroke) and YD-B (56mm x 50mm) — swept the first three places. Emboldened by these results, YMC executives set their sights across the horizon to America’s prized West Coast race, the Catalina GP. In preparation for the race Yamaha created what eventually became the YDS1, the S signifying that this was a sporty version of the existing model YD1.
The five Catalina-bound scramblers reportedly were prototypes based on the YD-B entries at the 1957 Asama race, each using a cassette gearbox that allowed mechanics to change gear ratios quickly. Four were ridden by seasoned American racers, the fifth by an upstart 19-year-old Japanese racer named Fumio Ito. Of the 32 starters in the 250cc division only 11 bikes finished, confirming how grueling the race was. None of the four American riders fared as well as Ito, who placed sixth, one position behind a fellow named Dave Ekins riding an NSU.
Stay West, young man, stay West
Yamaha later entrusted San Diego motorcycle dealer Sonny Angel with one of the Catalina bikes for a young man named Calvin Rayborn to race at local half-mile tracks. Wrote author Colin MacKellar in his book Yamaha, “The wins he achieved on the bike were an indication of great things to come.” Truly an understatement about the fledging brand from Japan as well as Rayborn himself.
Owner Pat Knopp and his restored 1960 YDS1 Scrambler.
No doubt, the YD1, and later YDS1, model represented a major leap for Yamaha in the way the fledging company developed its products. Buoyed by the YA1’s early success, YMC’s president, Genichi Kawakami, gave the go-ahead in 1956 for a new and modern research facility to be built in Hamamatsu, Japan. When completed he instructed engineers to develop a 250cc twin, basing their design on an existing West German brand’s 250. According to sources today, the group of six young engineers covertly produced their own blueprints of an all-new 250 twin instead. The result was the YD1, which was released to Japan’s domestic market April 1957. The initial run of bikes developed some mechanical issues that Yamaha quickly addressed, and by autumn of 1957 Yamaha had prepped a handful of racer versions (YD-A and YD-B) for the Asama race. Result: YD-Bs swept the first three positions in the 250cc class, while the YA1 once again dominated the 125cc class.
The YD-B racer prompted Yamaha to develop a sport version for consumers, initially called the 250 S, which had a modified YD1 engine with two carburetors as opposed to the engine’s original single-carb configuration, for more speed. After the 250 S’s initial production run in mid-1959 Yamaha changed the model name to YDS1. The groundwork had been laid for the YDS1 Scrambler that joined the product line for 1960.
The same, only different
While archival Catalina GP photos of Yamaha’s 1958 team bikes reveal rather crude-looking entries, the production-based 1960 Scrambler presented itself as a complete and ready-to-race bike, right down to its front number plate, upswept expansion chamber exhausts and knobby tires. Clearly, Yamaha had done its homework for its U.S. racer venture.
The new production racer’s overall fit and finish was first-rate, too. Prior to developing the new 250 YMC had sent personnel to scout the U.S. market, and their findings told them that bright colors with pearlescent or metallic overtones coupled with lots of chrome were the order of the day. The new YDS1 Scrambler showed up with those components, and in spades. Both fenders were chrome plated, as were the exhaust pipes, handlebar and wheel rims (a 19-inch up front for the U.S. model; the domestic-market Scrambler rode on an 18-inch).
The metallic-pearl paint found its way onto the bike as well, the YDS1’s striking two-tone gas tank and accompanying body trim remarkably stylish for the time. Even the stretched solo seat was fashioned specifically for this model, and the Yokohama knobby-tread tires meant that the 250 Scrambler was race-ready for the customer; just paint on your chosen racing number and go!
In truth, the Scrambler was a production-based bike offered in limited numbers (alongside the Racer intended for Class C oval-track and TT racing in America). Moreover, both production racers were based on the street-legal YDS1, a model that was targeted specifically at the U.S. market. And while the two racing variations might have sparked customers’ interest in Yamaha Motor Company, the YDS1 itself had all the attributes that marketing researchers had determined the American motorcyclists sought in a front-line model. Sales took off and Yamaha was on its way to becoming a key player in the U.S. motorcycle market.
The race-ready production racer’s air-cooled quarter-liter engine boasted a bore and stroke of 56mm x 50mm, fed by a pair of Mikuni VM20 carburetors. A rather high compression ratio for the time — 8:0 — and expansion chambers to help monitor intake and exhaust flow, contributed to a claimed maximum 20 horsepower at 7,500rpm. A wet, multi-plate clutch and 5-speed constant-mesh transmission completed the drivetrain to the bike’s chain drive.
Period literature shows the race-only Scrambler was lighter than the street-going YDS1, with a claimed dry weight of 291 pounds compared to the roadster’s 304 pounds. The Racer variation was lighter yet, checking in at a claimed 278 pounds. While the YDS1’s ignition system was battery-operated, both race bikes relied on flywheel-magneto ignitions for spark.
The engine was fully rebuilt during the restoration. When new, the 246cc parallel twin made 20 horsepower at 7,500rpm.
Clearly, the new YDS1 Scrambler had all the right stuff, as reported in the June 1960 issue of Motorcyclist: “NEW Grand Prix series of Yamaha models includes this Grand Prix Scrambler, a 250cc 2-stroke twin with a 5-speed gearbox, magneto ignition, double loop frame, upswept pipes, combination tachometer and speedometer, engine skid plate, chrome sports fenders, etc. Finished in Metallic Gold and White. Model was designed after their 1958 Catalina entry.”
Unscrambling this scrambler
Pat Knopp, a former racer and current Trailblazers member and trail-bike enthusiast who happens to earn his daily bread as a finish carpenter, encountered just such a bike advertised on eBay. A friend, who opted not to bid on what appeared to be a rusted-out 1960s-vintage Catalina Scrambler, told him about it. Pat gave the bike a look, and the more he examined it, the more he realized there was something special here. Precisely how special, he didn’t know at the time, but after “a ton of research,” he made top bid on it.
“After I bought it I didn’t take it apart until about a year and a half later,” Pat recalls. Translation: Over time it would be easy to have parts scattered in separate boxes throughout the garage until the whole project got away from him. Eventually, though, he began his parts quest, first locating the rare front fender from a collector in England who had been holding it in hopes of using the surviving fender for a similar rare model, Yamaha’s Liberty Ranch that had been earmarked for British and Australian sheep ranchers as a field workhorse.
Restoration was more than just a matter of hunting down old parts, though. Some of the Scrambler’s resurgence depended on Pat actually making completely new replacement parts, in some cases relying on new technology such as 3D printing to recreate them.
Pat knew nothing about 3D printing, so he attended a local college class to learn the actual technique. Next he shopped and bought the necessary 3D equipment before attending a trade show where he learned about rubber compounds to actually make items such as the gas tank’s knee grips, hand grips, and shifter and kickstarter rubber trim.
“Determining the rubber compound was a little challenging,” Pat admits, “but with the help of experts at the [dealer] show, I think I hit it pretty good.”
He also fabricated incidental parts. For instance, he made a die to stamp out the aluminum number plate, then had fellow Trailblazer Lee Fabry stamp it out on a 6-ton press. Next Pat built the number plate metal brackets from scratch. “I scaled them off parts I saw in manuals and photos,” he said about their proportions.
Pat leaned on some other Trailblazer contacts (Trailblazers is an affiliate of the Motorcycle Industry Council that recognizes pioneers and other figureheads of motorcycling’s past) for assistance, too. For instance, a long-established plating shop, EC Grinding in Santa Fe Springs, California, helped with the hard-chrome for the refurbished fork legs that the late Jim McMurren (also a member of the Trailblazers’ Hall of Fame and who actually raced a Scrambler back in the day) confirmed to be the right size. McMurren also helped Pat dial in the magneto’s timing. A local auto body repair shop assisted with reclaiming the battered rear fender, and Pat upholstered the seat himself. He also applied the striking paint colors that, to the best of his knowledge, are what the original bike wore.
The engine enjoyed a complete rebuild too. But Pat is reluctant to fire it up: “I’d hate to discolor the exhaust pipes,” he said, almost apolitically. Pity, because it’d sure be a treat to hear the crazy cackle from those stubby expansion chambers, no?
When all was said and done, Pat displayed the bike at the Tom Cates Memorial Bike Show that precedes every Trailblazers banquet. The 2019 show also happened to be the organization’s 75th anniversary gathering, so it was a rather landmark show as well. And, by show’s end, the reclaimed Scrambler wore the Best of Show ribbon, top prize. Not a bad legacy, perhaps surpassed only by the fact that this little Yammie represents the beginning of Yamaha Motor Corporation’s long run of providing American racers with some of the best racing equipment available to them. Ever. MC
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