1948 BSA A7 Sidecar Rig
The family twin is Wayne Dowler’s 1948 BSA A7 Sidecar Rig that was added when his family grew from two to three.
Wayne Dowler's 1948 BSA A7 sidecar rig.
Photo by Robert Smith
1948 BSA A7 Sidecar Rig
Power: 26hp @ 6,000rpm
Engine: 495cc OHV air-cooled parallel twin
Weight (cycle only/dry): 365lbs (166kg)
Fuel Capacity: 4.2 gal (16ltr)
Price then: $715 (approx., cycle only)
Price now: $3,000-$10,000 (cycle only)
The reproductive imperative is, of course, fundamental to our existence as a species. This has a number of serious implications for the dedicated motorcyclist.
First, the pursuit of love can seriously interfere with valuable riding and wrenching time. Second, the object of the pursuit may inexplicably turn out to have little interest in motorcycles (though careful planning can circumvent this). Thirdly, most motorcycles (Honda Super Cubs in Asia notwithstanding) only carry two people. So when love has been requited, and the fruit of this happy union is delivered, alternative transportation arrangements may be necessary.
Sadly, many motorcyclists take the easy way out and trade two wheels for four. However, the dedicated rider will recognize that parental responsibility is only temporary: Within 20 or so years, the offspring will fly the nest, having emptied both refrigerator and savings account. So for the truly committed yet impecunious biker, the solution is simple: add a sidecar.
A real Page Turner
Wayne Dowler’s 1948 BSA A7 and BSA sidecar outfit is a perfect example of family transportation of the day. Wayne’s sidecar is powered by BSA’s first parallel twin. Built from 1946-1950, the 495cc twin bears witness to several of Britain’s best motorcycle engineers. Valentine Page is credited with the basic layout, and had almost completed the design in 1939 before hostilities interrupted civilian bike development. Edward Turner of Triumph fame also worked on the A7 project while he was at BSA in the early 1940s, before BSA’s Herbert Perkins completed the detail work under Bert Hopwood’s supervision.
The production BSA A7 engine featured characteristics of the 1933 650cc parallel twin (the Model 6/1) that Page designed for Triumph, including the single camshaft mounted behind the cylinders. The long stroke (62mm x 82mm) engine produced a modest 26 horsepower at 6,000rpm and was mated to a BSA four-speed gearbox bolted to the back of the engine, just like Page’s 6/1. This was unusual for British bikes of the time, which typically had the gearbox bolted to the frame. Unit construction, which incorporated the transmission into the engine castings, wouldn’t arrive for another 15 years, and the A7’s “semi-unit” construction was carried over into the first-generation 650cc BSA A10 Golden Flash of 1950.
The BSA A7 powertrain went into a conventional lug-and-braze mild steel tube frame, but with somewhat ingenious use of the seat tube. Inside the tube was a serrated rod attached at the bottom to a steel T-bar that served as the centerstand. The stand was deployed by releasing a ratcheting handle on the seat tube, then pushing the stand down to the ground with one’s foot, locking it in place with a pawl. Another clever feature was a quickly detachable rear wheel and BSA’s patented “crinkle” hub that allowed the use of straight spokes with no bend where they pass through the hub, which stayed with BSA another 24 years.
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