Specifications
Engine, A.J.S. Design and Manufacture. Inclined Single Cylinder. Side-by-Side Valves. (74 x 93 m.m. Bore and Stroke, 399 c.c. capacity). Improved system of Mechanical Lubrication. Detachable Cylinder Head. Aluminium Piston. Roller Bearings to Big End of Connecting Rod Ball Bearing Main Shafts.
Frame, Semi-cradle, with Duplex Chainstays.
Three-Speed Countershaft Gear, Ratios,. 5.8, 8.51 and 15.46 to 1.
Clutch, Hand-controlled.
Footstarter, with enclosed operating mechanism.
Rear Wheel, A.J.S. Patent Quick Detachable.
Tyres, 26"x3.00" Wired-on Avon Heavy Non-skid. Rear Mudguard, Hinged.
Hubs, Taper Roller Bearing.
Carburettor, Amal with twist grip control.
Handlebars, New Type, with Steering Damper.
Footrests, adjustable to any position.
Brakes, Internal Expanding Front and Rear, quick adjustable.
Transmission, All Chain (Hans Renold), in. pitch, .305 width. Primary Drive enclosed. Rear Drive, the top half only is covered.
Shock Absorber, on Engine Shaft.
Saddle, adjustable.
Magneto, Lucas, mounted behind Engine. Stand, Central, Spring-up.
Rear Carrier, Detachable.
Tools, complete kit.
Wheel Base, 54¾ in.
Petrol Tank, capacity 2 gallons.
Oil Tank, capacity 4½ pints.
Weight, to standard specification, 278 lbs.
Extra for Lucas Magdyno Electric Lighting Set with Instrument Panel, as illustrated,
Extra for Lucas Magdyno Electric Lighting Set, without Instrument Panel,
Extra for 26" x 3.25" Tyres £0: 2:9
The Specification and Price is the same as the Model S4, except that the capacity is 349 c.c. instead of 399 cc in order to come under the 350 c.c. schedule for insurance.
Source: AJS Factory Catalogue 1931
