Readers' Rides: Martin Adams' Commonwealth Racing Norton

Readers' Rides
by Readers' Rides
We’re committed to finding, researching, and recommending the best products. We earn commissions from purchases you make using links in our articles. Learn more here

School of Hard Knocks (and Soft Cases)

If you were paying attention to American roadracing in the 1990s (more and more resembling a golden era), the name Martin Adams might ring a bell. Martin begat the Commonwealth Racing team, which in 1989 won its first AMA title: That would be the AMA Pro Twins GP championship (at the last corner, at the last round of the Series (Topeka), with Randy Renfrow in the saddle of the Commonwealth Honda RS850).

Later, when Camel sponsorship came to town in 1991 (remember tobacco?), Commonwealth became known as Smokin’ Joe’s Honda, winning four 600 AMA Supersport championships over the next seven seasons as well as more than a few Superbike races. When Honda’s new RC45 arrived on scene in 1995, Martin’s team won 19 0f 21 Superbike and Supersport races entered that year, with Miguel Duhamel taking both championships on the Smokin’ Joe’s RC and CBR600F3. Not bad.

Those were great motorcycles, too, but this story isn’t about them. It’s about Martin’s first racer, and our introductory Reader’s Ride: the Commonwealth Racing Norton he campaigned in 1984 and ’85. Our recent news posts about Norton’s current fiduciary woes started him down the memory lane of his own Norton misdeeds. Take it away, Mr. Adams:

“The name came from my being from the Commonwealth of Kentucky, our rider being from Great Britain, while our crew was Australian – the British Commonwealth of Nations. I knew just enough about Nortons to make myself dangerous. I had a Dunstall Commando. This was a Norton short-stroke 750 with bigger pistons, revised “squish” combustion chambers, and a one-piece lightened crank, netting – whatever! I had no dyno!! It seemed fast at the time!

“The twin contained a C.R. Axtell cam, increased inlet length (torque) with two late-model Amal concentric carbs (38mm, I think). Total loss ignition. A five-speed Quaife gearbox, with diaphragm dry clutch using a Gilmer belt for primary drive. Dry sump with oil cooler. Hand-made tank and seat from Norman White (UK). Marzocchi magnesium 38mm forks. Works Performance 18-inch rims. Performance Machine brakes… And a hugely modified fairing comprising a Norton top section and a Yamaha TZ750 lower. Exhausts were built in the UK by Mick Grant. The frame was a John Caffrey “Vendetta” from Wales (also UK). Norman White was principal builder.

readers rides martin adams commonwealth racing norton, John Caffrey Daytona 1987 with a later version of his Vendetta chassis containing the Honda flat track V twin that would evolve into the Commonwealth RS850
John Caffrey, Daytona, 1987, with a later version of his Vendetta chassis containing the Honda flat-track V-twin that would evolve into the Commonwealth RS850.

“It was light, about 325 pounds. Slippery aerodynamically. And, we assumed, ready to trouble old-style Ducatis. It WASN’T! Our rider, many times UK Historic Champion Dave Pither, was aboard at Daytona for the launch. He came in after a few laps looking paler than usual, and reported that it was nearly impossible to “hold a line of six feet” on the banking!

“I thought the shocks were not up to the banking’s loading. I stiffened them front and rear and right, back out you go! No improvement. Now, I realize the frame was likely flexing on the banking. This bike ran conventional slicks. But WORSE, we discovered the “potato chip consistency” of the motor’s crankcases… they actually cracked!!!

readers rides martin adams commonwealth racing norton, Seems the engine was stressed enough on its own before anybody even thought about making it part of the frame Don t you wish you had a Dodge Omni
Seems the engine was “stressed” enough on its own before anybody even thought about making it part of the frame. Don’t you wish you had a Dodge Omni?

“We raced it one or two more times after, working like Trojans on its tissue paper crankcases. They were unable, I think, to contain the pressures of a set of 850cc pistons at 7-8,000 rpm. Its cases were “pumping/breathing” without benefit of a proper breather; you could almost see it if you squinted. It was failure.

“I sold the bike to a US Navy missile engineer. I was broke, hugely disappointed, and trying to learn lessons… the main one was a word that repeated itself in my head: reliability! Thus began the eventual build of Commonwealth Racing’s Honda RS850/D, upon which Randy Renfrow won the 1989 Pro Twins GP Championship. Defeat is a two edged sword; discover the benign edge…”

Still, Martin doesn’t hold a grudge against British motorcycles: “In 1990 we won the Isle of Man Historic GP with a Triumph Trident we ran in the UK under the Team Commonweath Racing GB banner. We won so many championships/races there I cannot remember the total, also the Manx GP a few years earlier, with none other than Dave Pither. Live and learn.”

We’re suckers for nice photos and descriptive words and reasonably decent pics of your favorite motorcycle, or maybe just your most memorable one for all the wrong reasons? Send yours to, title it “Readers’ Rides,” and see yourself in this spot one of these weeks.

Readers' Rides
Readers' Rides

More by Readers' Rides

Join the conversation
3 of 5 comments
  • LookinKool LookinKool on Mar 28, 2020

    The engine was designed in the 1940's as a 500cc making maybe 35 HP. Became a 600/650/750/hi-compression 750/828 and all the change happened from the cylinder base gasket on up. Run a Commando hard and it'll blow out the cases and the gearbox. One must chill when riding one.

    Phil Schilling, "Cycle" magazine, 1974. Norton shut down in 1975...
    "The Norton vertical twin should have died and gone to legend a generation ago. In a world of perfect logic, engine designs should never maunder on for decades and finally be crushed by onrushing technology. Good ideas deserve better. Good engines should go to harvest in the fullness of their autumn; most mechanical things which struggle on simply die cold and wretched in December.
    Seasons do not cover England in perfect symmetry. Spring is cold and damp, and so is fall and winter. Onrushing technology there slows; the present walks in cadence with the past. And mechanical things like the Norton twin soldier on and on...through the Fifties...into the Sixties...and reach the mid-Seventies. In other places, someone would have raised the last hurrah at an earlier stage-when the original 500 twin turned to a 600, or 650, or 750, or 850. But somehow, no matter how deep Norton reaches into December, the final cheer never comes. There's only the next hurrah."

  • DickRuble DickRuble on Mar 28, 2020

    I thought the call was about what readers actually ride, the crazier, the more exotic, the more interesting. Not about distant memories of bikes they had come across or worked on or whatever.

    Does anyone ride a two-stroke on a daily basis, on the road, to work or to the store? Anyone riding a Bimota tessi to work a couple of days a week? Or a Montesa, or ... No garage/living room queens. Daily or semi-daily riders..

    About ten years ago, somewhere in Pennsylvania, in late afternoon rush hour I was passed by a Peraves.