The flying twin
Honda CB160 stock specs
Years made: 1965-1969
Claimed power: 16.5hp @ 10,000rpm
Top speed: 68mph
Engine: 161cc OHC parallel twin
Weight (wet): 294lb
Price then: $530 (1965)
Price now: $1,500 - $3,000
The tiny racer appears, sliding around the corner, with a baritone growl streaming from the twin exhausts on the Honda CB160 racer. There is a glimpse of black and silver, but in a blink, motorcycle and rider are rounding the next turn. The exhaust note lingers for a minute, and then disappears, chasing after the bike.
This small racer is homage to the first Honda race bikes. In 1959, the same year that Honda started exporting motorcycles to the United States, a factory team campaigning twin-cylinder 125cc racers appeared at the Isle of Man TT, then one of the most prestigious races in the world. None of Honda’s four entries placed, but the team won the Team Prize for reliability, learned as much as possible and took notes. Within two years, Honda was a serious threat in Grand Prix racing.
By this time, Honda had become one of the largest motorcycle companies in the world, selling small two-wheelers across Asia. From this secure base, company executives decided to mount an international race effort as a means to prove the quality of the Honda product and obtain good publicity in the U.S. and Europe, where they desired to expand.
Honda approached its racing effort the same way it approached developing new markets or designing new motorcycles. A company group was formed to learn as much as they could about the opportunities and pitfalls of the new project. Armed with this knowledge, the team looked for a technologically innovative way to approach its goal.
Honda’s factory race effort showcased advanced and intricate small-capacity machinery, including dual-overhead cam 50cc twins and a 5-cylinder 125. The company also developed production racers, most notably the 125cc CR93 twin. Some of this technology trickled down to the street machines. In July 1964, Honda introduced the CB160, a 161cc overhead cam parallel twin, to the American market.
Honda CB160 love affair
Then as now, the adjective most often used to describe the Honda's small racers of the 1960s was “jewel-like.” Like jewels, they were exquisitely designed and produced, and fascinating to consider. At least for gearheads like Ron Mousouris, who finds these little Hondas beguiling.
“I grew up with 1960s Hondas,” Ron explains. “I loved them. At one point, I started wondering how it was that Honda came here in 1959. I asked questions of a friend in Japan, who introduced me to Alan Siekman. He had a 1950s Honda, and sent me a photo of that bike in a field. The bike had so much character … I became so captivated I went to Japan.”
Ron has spent much of the last 15 years developing contacts for parts, rarities and knowledge among Japanese enthusiasts and collectors. His interest led him to open a restoration and repair facility for older Hondas, The Benly Shop, named after an early 125cc Honda racer.
In between stock restorations, Ron built this racer, which, like the racers of the early Sixties, could be described as jewel-like. Commissioned by Guy Webster, a well known photographer with a collection of beautiful small-displacement racers and exotic machinery, it was developed from a Honda CB160 street bike.
“Italian bikes are my mainstay,” explains Guy. “I had basically finished my Italian collection and was looking for something different. I remembered how I felt when I was younger and used to own a Honda. I souped it up and would race around the hills near my house on it. It was this wonderful feeling, the wonderful feeling of Honda.
“Ron is also a Ducati guy,” Guy continues. “I saw his work at different shows. He has a tenacity for perfection that suits my approach for restoration. I decided he would be the right person to build a beautiful jewel of a Honda racer for me.”
“Guy came to my shop in 2005,” Ron remembers. “He looked around at the Benlys. Eventually, he asked me if I would build a little Honda racer for him. He wanted me to do a bike that would work for the Motogiro or vintage racing. We settled on a Honda CB160 instead of the more commonly restored Superhawk. Both Guy and I like ‘tiddlers.’ Guy put the project in my hands and I ran with it.”
One reason for choosing the Honda CB160 was the rising interest in racing the little twins: Group W Racing in Seattle and Flying Circus in Portland have been racing with the Honda CB160 at Portland International Speedway and other venues in the Northwest and at the Bonneville VintageGP in Tooele, Utah. “The stock Honda CB160 is a wolf in sheep’s clothing,” Ron says, meaning it’s a perfect candidate for vintage racing.
The CB160’s little engine has a close relationship to the double overhead cam 125cc CR93 production racer of 1962 and 1963. It is very tunable and very user friendly. The intake manifolds are, as Ron notes, “the longest of any production Honda of the period. When fitted with the racing velocity stacks, they give the engine a clear, purposeful look.”
This Honda CB160 weighs about 265 pounds in stock form. It has an inherently light, well designed frame: Ron calls it “exquisite.” The engine is a stressed member, which helps to keep weight low while eliminating flex. Most recent GP bikes use this idea. Ron’s challenge was to take this small, light machine, designed for short-distance sporty street riding, and not only turn it into a serious racer, but also make it a thing of beauty: a jewel, like other small Honda racers. “Just because a bike is a race bike, doesn’t mean it can’t look good,” Ron says.
The process of turning a small but promising street bike into a jewel-like racer can be divided into two parts: improving the performance of the components of the bike, and cutting weight to the minimum consistent with good performance. Ron located a Honda CB160 that had been used in American Historic Racing Motorcycle Association (AHRMA) races in Utah. Some performance work had already been done, but Ron wasn’t satisfied.
He sent the engine to a machine shop, where the crank throws were sharpened and the entire rotating mass was balanced. When it came back, Ron added a tach drive and a cam with more pronounced contours and a different duration than stock. “The new cam produces a ‘lumpy’ sound — it’s the result of the change of valve opening duration,” he says.
Ron also did some mild intake porting and matched the head and manifold. The engine was bored to 181cc and compression was brought up to 10.5:1 from the stock 9.0:1. The exhaust system is the same length as the original (“I wanted to leave some turbulence there,” Ron says) but ends in hand-built megaphones instead of the stock mufflers. “The character of Sochiro Honda is evident in this bike,” he says. “The engine is a beautiful and resilient piece of Honda engineering.”
In contrast to the stock appearing engine, other parts were extensively reworked. “By Honda design, the CB160 is an inherently light bike, but to be competitive on the racetrack, it needed to be lighter still,” explains Ron. Several replacement components like foot controls and brackets are objects d’art in themselves.
Master metal worker Mike Shapiro was integrally involved in recrafting the rolling chassis, and he was especially involved in building the aluminum tank, a major project. “The goal in building this fuel tank was to make it lighter, lower, narrower, longer, more deeply sculpted, but still harmonized with the lines of the bike,” states Ron. “It was also key that the tank maintain the visual character of the original. The tank that we finally built for this bike was hand hammered over a wooden form sculpted by Mike.”
The tachometer and number plate mounts were also hand fabricated. Ron designed and made mounting hardware for the 200mm Oldani brakes and Takasago shouldered aluminum rims, dropping pounds of unsprung weight and helping to stop the bike in racing conditions.
The end result is a work of art that will run happily at almost 100mph. “I set out to make the finest little Honda possible,” Guy says. “I did it as an act of love. I wanted something different, something that would be a work of art. I knew the two of us together could do it.”
“As a restorer, when restoring a bike, whether a stock Benly or this racing Honda, if I don’t get the sense that my skills as a restorer have improved, that project was not a success,” Ron adds. “This was a wonderful project and I loved it from beginning to end. This bike is pure fun.”
Racing the Honda CB160
“It’s an enormously resilient little bike,” Ron says. “It will run hard, and after a hard run, the engine will start up and do it all over again.” The Honda has yet to see an actual race, although it has been run hard several times. Guy plans to take it to Willow Springs and Buttonwillow racetracks this fall for track days and exhibition runs. “Taking it out and breaking it in has been super fun,” Guy says.
The small engine and narrow tires demand a different cornering technique from modern racers with wide rear tires. “I’ve done a lot of racing on 175s, and you don’t brake hard and power out,” says Guy. “You brake before the turn and find a smooth line, powering through the turn at a reasonable torque, where you can control the tire slide on those thin tires.” Ron adds: “The CB comes out of the hole just fine. It pulls from 4,000 to 6,000rpm and comes on the cam at 6,500. It runs strong up to 9,000rpm. It will rev higher, but you’re not gaining anything, and the valves will start to float at 11,000rpm.”
Ron compares the Honda to a modern racer: “It performs similarly, but the rubber on the road is a lot smaller and the front end is not as stout. However, it’s very agile — you think of turning and it’s gone, because it weighs only 213 pounds with gas and oil.”
One area that has significantly evolved since 1964 is motorcycle brake technology. “You are always aware that although the brakes would be outstanding for this bike’s time, they are not the equivalent of triple discs with 6-piston calipers. The trick is to set up a rhythm as you ride,” says Guy. Although the thought of racing the 160 was part of the motivation of the build, Guy is presently undecided whether or not he is going to actually race the bike. “It is probably too developed at this point for Group W. I could race it under American Historic Racing Motorcycle Association rules, but I don’t know if I want to risk it. But,” he pauses and grins, “I might.” MC