Six cans of Tremclad are blown into the body of a 1930s classic as Alan’s Velocette MSS rises from the dead. Tremclad? What sacrilege, you say. Not really. Read on.
The Superior Springer
In the golden age of the British motorcycle industry, one type of bike predominated. Just as the four-cylinder DOHC bike became the Universal Japanese Motorcycle of the 1970s, the 500cc OHV four-stroke single became the flagship model for most British bike makers of the 1930s. Just about every major manufacturer made one, including: BSA, Triumph, Norton, Velocette, Sunbeam, Rudge, New Hudson, Excelsior, HRD, New Imperial, Royal Enfield and many more. One of the best was the Velocette MSS.
Velocette had been building road machines based on its race-winning 350cc KTT OHC bike from the mid 1920s onward. But the “cammy” engines were expensive to produce and left a large hole in their model range between the sporty OHC bikes and the company’s prosaic two-stroke 250cc GTP.
In June 1933, Velocette announced an innovative “square” 250cc OHV single with 68-by-68.25mm bore and stroke 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 over 70 mph according to period reports—very impressive for a 250cc machine of the era-and racing versions eventually reached 100 mph. So successful was the MOV that Velocette introduced a 350cc version, the extra capacity achieved by lengthening the stroke to a massive 96mm. This became the popular and durable MAC, followed by a further stretch, this time by increasing the bore to 81mm to create the 500cc MSS of 1935.
Intended primarily as a sidecar tug, the 500 proved to be equally proficient as a solo machine, and enjoyed a production run, as MSS and later as the 86-by-86mm Venom, that lasted 35 years until Velocette closed its doors in 1970. The Venom proved itself by running for 24 hours at over 100 mph at the Montlhery circuit in 1961—a record for 500s that still stands.
“The guy I bought [my Velocette MSS] from had it 37 years,” says Alan. “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 new Wiseco item intended for an ironhead Sportster, which happened to use the same dimensions. Inside the Velo’s iron cylinder head, he found a crack running from the sparkplug hole to the exhaust port—apparently a common problem with ironhead Velos. Relieving the ports and fitting hardened steel valve seats seems to have the problem under control-if anything, the crack has got smaller, says Alan.
New front and rear fenders to the correct pattern were sourced in the UK, and the whole bike was treated to some new paint. Parsimonious by nature, the new owner did the painting himself using up six rattle-cans of black Tremclad! The finish actually looks a lot more 1930s authentic than powdercoating.
Ignition on the MSS is by BTH magneto with a Lucas E3L dynamo for lighting. Initially, Alan replaced the Dynamo with an Alton alternator, but that failed. After returning the offending item, its warranty replacement was “dead out of the box.” Finally, Alan refitted the E3L, but installed a 12-volt conversion. Lighting is improved, he says, and replacement bulbs easier to find.
“The MSS is similar to a Norton model 18 in terms of power,” says Alan, “but the Velo was a bit more of a handmade bike.” The use of a narrow crankcase means the engine is exceptionally rigid, he says, and there’s “not much vibration.”
The girder fork used on Alan’s 1938 MSS is a Webb type: Velocette continued with the setup to 1948, when they switched to Dowty Oleomatic telescopic forks. Minimalist Alan seems to like the Webbs’ austere nature.
“They’re dirt simple,” he says. “Keep ‘em greased and they’re good.”
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.”
The types of girder (“springer”) forks found on motorcycles fall broadly into two main categories: leading link (Harley-Davidson, Castle); and parallelogram (Druid, Webb, Brampton).
Webb-type girder forks, as fitted to the MSS, have pivot points and/or sliders that need to be kept well-greased. Even so, bushings will wear over time and may need to be replaced, especially if maintenance has been neglected. Spindles are made of special steels, and only replacements designed for fork applications should be used.
Girder forks need regular inspection for cracks and signs of rust in the fork legs, too. The slender tubes used on Webb and Brampton forks are especially prone to rusting from the inside. And before fitting any set of used girder forks, make sure they’re strong enough. Many manufacturers produced forks using different size tubing for different applications. Norton, for example, built a heavyweight fork from tubes that tapered from about 7/8-inch O.D. down to 5/8, and a lightweight fork tapering from about 3/4-inch down to one-half.
Alan offers these final words of advice for Webb-type springer owners:
“The main adjustment is in the spindles, he says. “The spindles should be tightened until it’s only just possible to turn them with your fingers.
“Keep the friction damper tight. If something comes loose, it’s usually obvious!”
-Robert Smith (issue #281)