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Rare Racer: 1962 Honda CR72

Here’s something you don’t think about very much, unless it’s not working: your cam drive. As most of us ride modern motorcycles with dual overhead cams, we take for granted the smooth, quiet and reliable nature of the cam chains and tensioners that keep our camshafts opening and closing valves many thousands of times every minute, mile after mile, year after year.

It wasn’t always so. Honda is now well-known for making single and dual overhead cam motors, most famously the CB750, but back in the early ’60s the company’s engineers struggled with getting chain-driven cams to run as precisely and reliably at high rpm as the gear-driven equipment on the factory racers. Honda had been using overhead cams in its small-displacement street bikes, but to dominate the world motorcycle market it needed a way to inexpensively and reliably provide big-bike power, power that would shame and humiliate the older OEMs like Triumph, Norton and Harley-Davidson.

This bike is one stop on the way to the famed CB750, the model that paved the way for Japanese dominance of motorcycling, a dominance that only now, almost a half century later, is starting to crack. You won’t find it in any spotters guides and you certainly won’t find it parked outside your local Starbucks. It’s a rare and interesting 1962 Honda CR72 street bike owned by Ron Mousouris. It’s the only one known to exist.

It looks a lot like a CB72 Hawk, but vintage-Honda enthusiasts will point out the unique motor. The motorcycle is the result of Honda’s R&D department fitting a one-off CR72 race motor into a CB72 Hawk chassis, probably for testing and evaluation purposes. According to the Classic Japanese Motorcycle Club‘s Allan Seikman, who showed me the bike at the recent Clubman’s Weekend at the San Jose fairgrounds, the engine ( serial number 300001) looks very much like a CR72 unit, complete with magnesium bits and distinctive cam covers for the dual camshafts. It is fitted with a six-foot-long cam chain, and some parts look like those off the later CB450.

This bike’s history is murky and the story I got may be hearsay—but it’s all the information I could find. Seikman tells me the motorcycle was used as a development testbed in Japan and then sold to a U.S. serviceman stationed there. He raced the bike in Japan and then in the U.S. after he returned home. At some point, the motor “blew up,” and the guy sold it to a Honda dealer, where it languished for decades.

Enter Ron Mousouris, owner of the Benly Shop, where he restores vintage Hondas. He acquired the bike, and since it was not in the state it was in when it left Honda’s R&D department many years ago—to say the least—he replaced everything but the original engine. That means the bike you see here is, except for the unique powerplant, in essence a replica—but that doesn’t diminish the visual impact of the project. Stock CB72 and other vintage components were carefully located, modified and restored to produce a close recreation of how the bike originally looked. See some of the build thread here.

Regardless of originality, the historical import of this bike made it thrilling to see in person. Reliable overhead-cam engines led to the CB450, CB350, CB750 and other smooth, fast and reliable bikes like the Z1 and GS750. Thanks go out to guys like Allan and Ron for keeping history alive.

27 Comments

  1. Butch says:

    There’s just something about a dual overhead cam engine, especially singles and twins.
    The CB/CL 450 Hondas sold in the late 60’s through 74′ were some of the coolest motors ever produced for the mass market.
    I used to spank the single carb BSA and Triumphs on a regular basis with mine back in the day.

  2. Artem says:

    I was looking around (Greece).
    With the girl wanting a discotek.
    it was a Gilera scooter.
    very cool.

  3. Michael says:

    Thanks for the article on this exceedingly rare bike. But your “back in the early ’60s the company’s engineers struggled with getting chain-driven cams to run as precisely and reliably at high rpm as the gear-driven equipment on the factory racers” is excessively generous to Honda!

    In the late 70s and early 80s they had big problems with the CX 500 & CBX 550, leading the much lamented journalist John Robinson to conclude (from memory) that “when it comes to getting valvegear to spin reliably at high RPM, Honda are not in the first three”.

    RIP JR

    • GuyLR says:

      I’m not sure about the CBX500 but the CX500 didn’t have a problem with valves at high rpm. It was a pushrod engine by the way with a single camshaft driven by a hyvo chain. It was redlined at 9750 but the stockers that we endurance raced would pull past that up to 10,300 or higher every lap all day long. We ran them in two 30 hour races at Rockingham in 1979 and 1980 and they were dead nuts reliable at race speeds.

      • MGNorge says:

        Right you are, the CX500/CX650 engines were high cam engines employing short pushrods that allowed higher rpm than otherwise would be possible. The CX line had their niggles but cam chain problems were not the problem. Cam chain tensioners and their designs changed in many engines, not just Hondas.

  4. GuyLR says:

    That’s a beautiful engine and a great restoration. Only the serial number prefix double strike on the engine case is a little worrying but who cares?

    The CR72/77s looked to be the hot setup for club racers in Japan until the first TD1 Yamahas showed up in mid 1962. From then on the Hondas must have been interesting to see and hear but rarely winners.

    Here’s a good write up on the TD1 that mentions the CRs.

    http://www.classicyams.com/production-racers/productionracers/birth-of-the-yamaha-tds.html

  5. Gus says:

    We usually don’t think of Honda of that era in stylistic terms, but I think that combined tach/speedo/vertical odo is beautifully simple and elegant. Thanks for the picture.

  6. Gunner S says:

    No, the early Honda CRs were based more or less completely on the NSU twin racers from the 50’s. Of course, there was influence from the MVs and the Gileras, but look at the layout and design of the NSU twins and you’ll see where they got their inspiration.

    • Jake says:

      I agree ‘Gunner S’ — when it comes to race-bikes, Mr. Honda was probably greatly influenced by the fabulous NSU racers of the ’50s.
      As would be anyone who was paying attention at the time..!

  7. paul246 says:

    Wow, that is something else. Makes one realize how much we just take for granted.

  8. todder says:

    Very nice bike. Love these old designs, they get me passionate again over old honda’s and my girlfriend really likes the styling.

  9. MGNorge says:

    Love them Hondas, such engineering and racing history. That Honda was willing to step out and improve upon these designs says a lot of them at a time when other Japanese companies stayed with two-strokes and the Europeans didn’t take them seriously. Just the thing to keep a young boys wonderment at all things mechanical at a peak. Couldn’t wait to get a piece of it!

  10. Mike Simmons says:

    When I was a pup, I worked at a Honda dealer in St. Louis. I owned a CB77 Super Hawk at the time. One day while I had some time on my hands I went thru the parts manual and found a refernce to a CR77. Rear set pegs, lowered bars, relocated shift and brake linkage…. hmmmmm thought I, I wonder if I could convert my CB into a CR? Sooooo, I placed a parts order thru Gardena for the requistite CR parts and was notified that they would have to come from Japan. I accepted the long wait and placed the order. Several months went by and one day a package showed up at the shop with all my parts. I then converted my CB into a CR (minus the cylinder head). I was a very cool bike that I wish I still had. Thanks for the article, It really brought back some memories.

    Mike

  11. mickey says:

    Very cool. Motor looks very 1950s-1960 s Italian actually. I see where Moto Guzzi got the inspiration for the gas tanks on their new 1400 s ha ha.

    • MUSTAFA IBRAHIM says:

      Mr. Honda bought a few engines from one of the Italian manufacturers who quit racing after 1957. The early Honda GP bikes were based on those. Hence the “Italian” look. See Kevin Cameron’s excellent book on race engines for details.

  12. MUSTAFA IBRAHIM says:

    Whoa, now that is really something. Thanks for this one – it is gorgeous.

  13. Michael_H says:

    Mr. Honda was a passionate genius. The company he founded (and the culture he created in that company) deserves every success it has.

    • Norm G. says:

      re: “Mr. Honda was a passionate genius.”

      soichiro was “pimp”, as all the cool kids would say.

      • Gutterslob says:

        As far as Japan is concerned, he was “The Pimp”. The boy built a race car out of a junked aircraft engine when he was 16. Also rumored to have tested a jetpack by himself. He was a one-man skunkworks.

        Sadly, Honda wasn’t quite the same company after Soichiro-san passed. If he were still around, they would have never ended their partnership with McLaren in the early 90’s (just a year after his death), they would have made road-legal RC models way more often, and the McLaren F1 road car would have probably been powered by a Honda motor instead of the BMW one.