Language Barrier: The 1971 Bridgestone Mach II SS
Engine: 198cc air-cooled rotary induction 2-stroke parallel twin, 53mm x 45mm bore and stroke, 21hp @ 8,000rpm (claimed)
Weight (dry): 274lb (124 kg)
Fuel capacity/MPG: 2.64gal (10ltr)/40-50mpg (est.)
Price then/now: $625/$2,000-$4,000
Here’s a story that features plenty of BS. And before anyone gets huffy about our language, let’s set something straight: BS stands for Bridgestone, as in Bridgestone motorcycles.
Early in its history, the Japanese manufacturer shortened its name to BS. Looking back, the decision to use those two simple initials seems a poorly considered marketing decision. Yet it didn’t seem to work against the company, which became known for its high quality, innovative, 2-stroke motorcycles.
A little Bridgestone history
Bridgestone’s roots go back to 1931, when Shojiro Ishibashi founded the Bridgestone Tire Company, so named because in English Ishibashi’s last name translated into stone (ishi) bridge (bashi). He reversed the order of the words to form Bridgestone, and the company produced tires and a number of other rubber goods.
After World War II, Ishibashi began looking for other products to manufacture. Bridgestone first got involved in automotive parts, but Ishibashi recognized Japan’s need for economical and reliable personal transportation. He began building bicycles in 1946, and by 1950 was pursuing the marriage of bicycles and engines with Bridgestone Cycle Industries.
Through an arrangement with Fuji Precision Engineering Co., Bridgestone sold 26cc engines. Called the BS Motor, they were simple friction-drive clip-on units that fit over the rear wheel of a bicycle. By 1953, Bridgestone was offering the complete BS-21 Bambi, its own bicycle and Fuji clip-on engine, and before too long the engine had grown to 49cc. With the Bambi selling well, Bridgestone decided to begin producing full-fledged mopeds and motorcycles.
To meet this goal, the company had to hire designers and engineers, many of them from other Japanese motorcycle manufacturers such as Marusho and Tohatsu. In 1958, Bridgestone introduced the Champion moped with a pressed- steel frame, 24-inch wheels and a 50cc 2-stroke engine equipped with pedals for starting. It looked very similar to the NSU Quickly.
Bridgestone didn’t have room in its own factory for production, so the machines were built by Fuji. After opening a new manufacturing plant in Ageo, Japan, Bridgestone assumed full production.
By 1963 Bridgestone had several models based on the Champion (which by then had been redesigned to be more conventional looking, with a backbone-mounted gas tank and smaller, 18-inch wheels), and had also created several new prototypes, none of which ever saw full-scale production. What did come out of the factory, though, was the new BS90, a single-cylinder rotary valve 2-stroke. At the same time, Bridgestone began exporting the BS7, a moped based on the Champion 2-stroke, through the Rockford Scooter Co., Inc. of Rockford, Illinois.
Bridgestone in the U.S.
A December 1963 issue of American Motorcyclist cited Rockford as the sole U.S. agent for Bridgestone, noting that Rockford had begun utilizing its own airplanes “to streamline communications with its dealer organization” and provide parts and support. American dealers were often small lawn mower and equipment sales and service shops, while some larger regional department stores also sold Bridgestone and rebadged Bridgestone products.
Rockford Scooter was later renamed Rockford Motors, and by 1965 the company was Bridgestone’s most important retailer thanks to the lucrative American market it served. A new bike, the BS175 Dual Twin, was launched in 1966. Featuring a 175cc 2-stroke parallel twin with dual carburetors and rotary valve intake, the Dual Twin was, Cycle magazine wrote in a March 1966 test, “by all specs a doubled-up 90cc Bridgestone ‘Sport.’”
Bore and stroke for each cylinder was the same as the single. The rotary intake valves were placed outboard on each side of the crankshaft, fed by carburetors completely enclosed under alloy side covers and drawing air piped in through a paper filter.
Ignition and generator components were combined into a single unit placed behind the alloy cylinders, which featured chrome-plated bores. Oil-injection was a standard feature, and a unique feature of the machine was the “Sport Shift” dual-mode transmission, which featured a small hand-operated lever high on the left side of the transmission. Shifting the lever forward put the transmission into a 4-speed rotary shift pattern, with neutral between fourth gear and first gear, and with the gear pattern repeated endlessly by pressing down on the foot shift. Shifting the lever rearward brought an overdrive fifth gear into play and made the transmission shift in the regular one down, four up pattern, with neutral between first and second gear.
At the 1966 Tokyo Motor Show, Bridgestone showed off the prototype café racer style BS200 Mach I. Based on a BS175 engine with enlarged bores, this motorcycle was never put into production, but in 1968 Bridgestone put the 200 engine into the running gear of the Dual Twin, creating the BS200 Mach II. Available in RS for Road Sport and SS for Street Scrambler models, the motorcycle enjoyed a four-year production run, until 1971. By this time, Bridgestone had been slowing down new model development and eventually decided to focus solely on tire production, leaving motorcycles behind.
Carlos Santana’s Mach II SS
30-year-old Carlos Santana got interested in motorcycles about 10 years ago, and it was his enthusiasm for speed and handling that led him to swing a leg over a bike. A 2003 Honda CBR600RR was his first machine, and it remains a focal point in his growing collection. In 2007, Carlos went to the Larz Anderson Auto Museum in Brookline, Massachusetts, to attend the Japanese Day festivities. He was looking for a vintage Datsun 1600 roadster and wanted to establish some contacts. At the show, he saw a café-style Honda CB160. He liked it, and spoke at length to the owner. When he got home, he started searching for an older CB160. He found one, bought it, brought it back to original spec and rode it for some time.
Carlos also bought a vintage 1968 Datsun because of that show, and he became friends with Charlie Ellis, a member of the Datsun Roadster Owners of New England club. Charlie told Carlos about an old motorcycle in his barn, telling him if he was interested, he could have it.
Rusty but rare
The barn-find machine was a last year 1971 Mach II SS (also called the Mach II SS-7 in some Rockford ads), with twin high pipes, a suede-topped non-slip saddle and cross-braced motocross-style handlebar. The Mach II’s engine featured all that the Dual Twin of 1966 had, including the unique transmission shift pattern that could be changed with the flick of a lever. Charlie’s father-in-law was the first owner of the 198cc machine, and after less than 3,300 miles he lost interest in riding and simply put it away.
It wasn’t in exactly great shape as found in the musty barn, but Carlos decided that because of its rarity, the Mach II was worth saving. “The gas tank had rotted through at the bottom, the engine was seized and the carbs were gummed up. But it was 100-percent complete,” Carlos says. For 1971, the RS and SS models could be purchased in Imperial Gold — the color of Carlos’ bike — or Sequoia Green.
Carlos wanted to get the bike running, leaving it in its “survivor” state, but he couldn’t free the stuck pistons. That’s when he decided the SS needed a complete restoration, and although capable of such a chore, Carlos delegated much of the work to his friend Joe Weaver at DWMS Racing in Alabama.
Carlos is from a family of gear heads. His dad, Ed, was a rally car navigator and enjoys turning wrenches. Carlos’ mother, Gloria, and his older brother, Eddie, support their mechanical adventures, although they don’t get too greasy. Ed and Carlos work together on mechanical projects in the Santana family two-car garage, and on evenings or weekends it’s easy for Carlos to make the 2.5-mile trek across town to work on projects.
The restoration begins
Before crating and shipping the Bridgestone to Joe’s shop, Carlos removed the gas tank, seat and rear grab bar. After it arrived in Alabama, Joe took photographs of the project bike, dismantled it, and made a list of all the pieces required. Carlos was responsible for finding all parts, including a replacement gas tank and a pair of cylinders — one left and one right. Working the Internet and the telephone, Carlos secured a used gas tank and a set of cylinders. Many new-old-stock parts including cables, grips and mirrors were found online. Yet the majority of his Bridgestone is comprised of original, albeit refurbished, components — including the rubber fork gaiters.
In the engine department, the replacement cylinders were sent to Millennium Technologies in Plymouth, Wisconsin, where they were returned to standard bore and Nikasil plated. Meanwhile, Joe bead-blasted the cylinder head, cylinders and cases and polished the engine side covers. New bearings, seals and pistons were used to put the engine together.
Joe stripped the frame and center stand, and then painted them black. The rear shocks and front forks were in good shape, but required repainting to bring them back to life. The wheels were stripped and the hubs were polished before being put back together with replacement spokes and rims shod in, what else, Bridgestone tires. The headlight bucket, handlebars, rear fender, exhaust header pipes and rear axle adjusters were sent out for chrome plating. Joe bumped out a couple of dents in the stainless steel front fender before polishing it up. The exhaust baffles had rust holes in places, and Joe cut out the affected metal and welded in patches before painting them black; the heat shields are factory original stainless steel, polished in Joe’s shop. Joe’s brother, Jason, painted the gas tank, oil tank and side panel as close to the original Imperial Gold color as possible. “Most of that bike is factory original parts that have been cleaned and polished,” Joe says. “Even the taillight lens and the bulb in the headlight are original.”
A sticking point in the restoration was locating a correct seat cover. Carlos hired someone to make a replica, but wasn’t happy with the result. “Joe was nearly done, and I thought the build was in jeopardy because I couldn’t find someone to make an accurate cover with the regular vinyl around the bottom and the crushed suede on top,” Carlos says. “But, on many forums people were recommending a guy in Thailand, so I sent him what was left of the original cover for him to replicate. I thought it was a scam, because he gave me a fair price, and said I’d have it in two weeks. Well, he delivered. And it looks great.”
This is Carlos’ first 2-stroke motorcycle, and to play it safe, he decided to bypass the automatic oil injection system in favor of running premixed gas and oil; he’s quite happy with how it runs. “First or second kick and it’ll fire up, and it’s a screamer on the road,” Carlos says. “Get up in the power band and it just wants to go. It responds immediately, and it’s a blast riding through a canyon with a twisty road — she goes right through it.”
It’s too bad Bridgestone didn’t stick to motorcycles, because if the Mach II SS is any indication, they built some of the best in the business. And that’s no BS. MC
Bridgestone: Back to basics
When Bridgestone dropped motorcycle manufacturing from its product portfolio after the 1971 model run, rumor had it that Bridgestone’s rivals — led by Honda — were pressuring the company to decide if it wanted to be a tire manufacturer or a motorcycle manufacturer. Keep making motorcycles, the rumor said, and Honda and the rest would shop elsewhere for tires. According to a history of Bridgestone motorcycles written by Graham Weeks and published in the Vintage Japanese Motorcycle Club Newsletter in 1996, the real reason hinged on the tire and motorcycle divisions’ shared manufacturing space. Motorcycles were basically a sideline for Bridgestone; when the tire division needed room to grow, the axe fell on motorcycles. After closing its motorcycle division, Bridgestone sold the manufacturing rights and all tooling for its 60cc and 100cc singles to BS Tailung in Taiwan, which supplied Rockford Motors with trail and mini-bikes like the Tora, Taka and Chibi until 1975.
It’s Time to Start Thinking About Winterizing Your Motorcycle
As fall approaches, we’re covering the basics of winter storage.
How to Rebuild a BMW Front Brake Master Cylinder
Follow along as Keith Fellenstein repairs a brake master cylinder in this step-by-step guide.
Terrestrial Flyer: 1954 MV Agusta 175 CSS Disco Volante
Read about three beautiful motorcycles: the MV Agusta 175 CSS Disco Volante, the Aermacchi Chimera 175, and the Motobi Catria Lusso.