Two of the best representatives of girder-forked 500cc British singles
The 1936 Norton Model 18 (left) and the 1938 Velocette MSS.
The 1930s were the golden age of the British motorcycle industry. And just as the four-cylinder DOHC became the signature for the UJM — Universal Japanese Motorcycle — of the 1980s, the 500cc OHV four-stroke single with girder forks was the default UBB — Universal Brit Bike — of the era.
Just about every major British manufacturer made a 500cc single — BSA, Triumph, Norton, Velocette, Sunbeam, Rudge, New Hudson, Excelsior, HRD, New Imperial, Royal Enfield, they all had one. But two of the best were the 1936 Norton Model 18 and the 1938 Velocette MSS.
Norton built its first overhead valve single in 1923, the 500cc Model 18. An instant success both on the street and the track, a Model 18 took Alec Bennett to the winner’s podium at the Isle of Man TT in 1924.
In 1927, Bennett again won the TT, but this time on a new Norton, the CS1 with its Walter Moore-designed overhead camshaft engine. In 1928, the “cammy” CS1 appeared in Norton’s catalog, together with a new street bike using an overhead valve engine that borrowed heavily from the CS1, the ES2. All three machines shared the same 79mm bore by 100mm stroke, numbers used on every road-going 500cc Norton single for 40 years until the last ES2 of 1963. Though almost identical to the Model 18 on paper, the ES2 included many detail improvements over the 18 and was sold alongside it until the Model 18 was dropped in 1947. Even so, it was the 18 that earned Norton its sporting reputation in the 1930s.
Velocette had been building road machines based on its race-winning 350cc KTT overhead cam bike from the late 1920s onward. But the “cammy” engines were expensive to produce and left a big hole in Velocette’s model range, with the sporty overhead cam bikes on one end and the company’s prosaic two-stroke 250cc GTP on the other.
In June 1933, Velocette announced an innovative 250cc overhead valve single to bridge the gap. In order to minimize the reciprocating mass in the valve train, the camshaft was positioned as high as possible, keeping the pushrods short. The model MOV had a top speed of 60mph right out of the box, very impressive for a 250cc machine of the era, and tuned versions eventually reached 100mph. So successful was the MOV that Velocette introduced a longer stroke 350cc version, which became the MAC. The big bore 500cc MSS followed in 1935. Intended primarily as a sidecar tug, the MSS proved to be equally proficient as a solo machine, and enjoyed a production run (as MSS and later as the Venom) that lasted 35 years, until Velocette closed in 1971.
Importantly, both Velocette and Norton could point to outstanding racing success with their singles, too: From 1923 to 1939, Norton won 11 500cc Senior TTs at the Isle of Man, while Velocette won five 350cc Juniors.
In fact, the Norton and Velocette singles were so popular they came to represent Thirties British motorcycles better than perhaps any other machines. Yes, you could buy a Brough Superior or a Vincent, but those were limited production machines made for the very discerning; they were not the sort of bikes the average rider could afford. And while you could also opt for a two-stroke Scott Flying Squirrel or an opposed-twin Douglas Endeavour, neither of those could match the market appeal of the Norton and Velo.
And while the Norton and Velocette are certainly getting harder to find today, they still represent an excellent opportunity for classic — some would say vintage — motorcycle ownership, as the owners of our two feature bikes will attest.
This is not, we should note, an old school shootout. We didn’t pin the throttles on the 1938 Velocette MSS and 1936 Norton Model 18 we gathered together for this review. Nor did we dump their clutches and redline them through the standing quarter mile. Last time I tried that on an old Norton single, the result was a big bang and a pool of oil. But owners Steve Snoen and Alan Comfort did enter into the spirit and run their bikes side by side for the camera.
Neither of their bikes is a trailer queen. Both get exercised regularly and ridden hard — or as hard as they were intended to be. The Norton 18 was designed as a race bike, so it’s pretty rugged, and of course the Velocette 500cc engine also proved itself later in production racing — especially in the 500-mile race at the Thruxton circuit in southern England.
1936 Norton Model 18
Claimed power: 21hp @ 5,000rpm
Top speed: N/A
Engine: 490cc air-cooled OHV single w/exposed valve springs
Weight: 374lb (170kg)
Fuel capacity: 5gal/19ltr (approx.)
Price then/now: $293 (est.) / $4,000 - $10,000
Steve Snoen bought his 1936 Norton Model 18 from a 72-year-old gent in Edmonton, Alberta, Canada, who had imported it from the U.K. The only work Steve has done so far is to replace the rear brake pull rod, which was stripped. “It runs well,” Steve says. “The brakes are good, and it starts easily hot or cold. To enjoy it, you just have to not be in a hurry. The gear change is slow and awkward at times, so you have to give it plenty of time.”
Steve is planning to ride his Norton the 6,000-odd miles round trip from Vancouver to the International Norton Owners Association rally near Woodstock, N.Y., in 2011. And I wouldn’t bet against him. A few years back, Steve rode his 1956 BSA C12 250 to the BSA rally in New England — 7,000 miles round trip! Right now he’s rebuilding the 18’s engine and gearbox to improve shifting and to cure some oil consumption issues.
Why the Model 18? Steve saw a 1946 version in a local collection and decided he wanted one, so he started advertising in the wanted-to-buy columns. And just like buses, two came along at once. Steve had just closed the deal on the 1936 bike in Edmonton when well-known California Norton collector Art Sirota called with a 1947 Model 18 for sale. What to do? In the end, Steve bought both. Between 1936 and 1947, the only apparent changes were Norton Roadholder telescopic forks instead of the Webb-type girder used earlier, and enclosed valve gear. So that gives Steve a unique perspective in being able to compare two almost identical machines — one girder, one tele.
What’s the girder fork like to ride? “It’s much harsher on the front,” Steve says. “Bumps transfer through to your arms much more. It’s best to anticipate potholes and speed bumps. But it’s really not bad when you consider that it is from the mid-1930s.”
Girder forks were notorious for loosening up and compromising handling, so is wear an issue? And what maintenance is required? Not much, it seems. “The bushings have grease nipples, so I give them a shot about every 1,000 miles. Wear hasn’t been a problem yet,” Steve says.
1938 Velocette MSS
Claimed power: 23hp @ 5,000rpm
Top speed: N/A
Engine: 495cc air-cooled OHV single
Weight: 340lb (154kg)
Fuel capacity: 5gal/19ltr (approx.)
Price then/now: $342 (est.) / $5,000 - $14,000
“The guy I bought it from had it 37 years,” says 1938 Velocette MSS owner Alan Comfort. “He’d started on some minor restoration, partially dismantling the bike. In the process, he lost a lot of stuff, mostly fenders and other sheet metal pieces.”
Alan bought the bike as a non-runner and first set to work on the engine. The piston was replaced with a Wiseco item for an iron-head Sportster, which happens to use the same dimensions. Inside the Velo’s iron cylinder head, Alan found a crack running from the spark plug hole to the exhaust port — apparently a common problem. Relieving the ports and fitting hardened steel valve seats seems to have the problem under control; if anything, the crack has gotten smaller, Alan says.
New front and rear fenders to the correct pattern were sourced in the U.K., and the bike was treated to new paint. Parsimonious by nature, Alan did the painting himself — six rattle-cans of black Tremclad! The finish actually looks a lot more authentic than powder coating.
Ignition on the MSS is by BTH magneto with a Lucas E3L generator for lighting. Initially, Alan replaced the generator with an Alton alternator, but that failed. And its warranty replacement was “dead out of the box,” he says. Finally, Alan re-fitted the E3L with a 12-volt conversion. He says lighting is improved, and replacement bulbs are easier to find. “The MSS is similar to the Model 18 in terms of power,” Alan says, “but the Velo was a bit more of a handmade bike.” The use of a narrow crankcase means the engine is exceptionally rigid, and Alan says there’s not much vibration.
Like Steve’s Norton, the girder fork used on Alan’s 1938 MSS is also a Webb type, which Velocette used until 1948, when they switched to Dowty Oleomatic telescopic forks. Minimalist Alan seems to like the Webb forks’ austere nature. “They’re dirt simple,” he says. “Keep ‘em greased and they’re good.” He also advises keeping the friction damper tight. “The main adjustment is in the spindles. The spindles should be tightened until it’s only just possible to turn them with your fingers. If something comes loose, it’s usually obvious!” OK, but how well do they work?
“They’re anti-dive, for sure,” he says with a wry smile, “and they don’t leak oil,” though he admits to deliberately avoiding potholes, which do show up the girders’ inadequacies. “If you’re following someone on a bike with a girder fork, you’d probably think they were drunk.”
Although improved telescopic forks eventually rendered girder forks obsolete, it’s interesting to note that in 1988 Harley-Davidson, in a nostalgic nod to the past, reintroduced its iconic “springer” girder fork. And while owners Steve and Alan probably won’t be rushing out to buy a Harley Springer anytime soon, neither will they be parting with their old girders — fun, eminently rideable machines that remind them of a simpler time. MC
Read more: A Brief History of Girder Forks