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BSA Motorcycles

The 1.74 h.p. Two-stroke.

This is a machine which anyone can learn to ride in a few minutes, for it is extremely light, comfortable, and easy to handle.

Engine.
This is a single cylinder, 1.74 h.p. two-stroke, with a bore and stroke of 60 x 61.5 mm. respectively. The piston is of aluminium alloy. A roller big-end bearing is fitted, and the engine mainshaft is mounted on two ball hearings. Petroil lubrication is standardized. A kick-starter is fitted engaging direct with the engine shaft. A fly-wheel cover can be obtained at a, slight extra cost.

Carburettor and Ignition.
The carburettor is of the Amac two-lever type. Ignition is effected by a high tension magneto gear driven from the engine and mounted behind the cylinder.

Transmission.
Enclosed gear drive from the engine to the layshaft, running in oil, and final drive by means of ½ in. pitch x .305 in. roller chains amply protected by an efficient guard. The floating dry-plate clutch, is mounted on the layshaft, and is controlled by a lever on the left of the handlebars.

Gearbox.
A two-speed gear-box is fitted, in unit construction with the engine, the gears being constantly in mesh and changes being effected by dog clutches. The layshaft is mounted on two ball bearings. Gear ratios are given on page 63.[1]

Frame and Forks.
The frame is of the duplex type, designed to give a low riding position and a low centre of gravity. It is built up of steel tubes reinforced, which are trapped and bolted at the ends to eliminate brazed joints. Lubrication to the hub and frame parts is by means of a grease gun. A rear stand of the kick-up type and a, strong carrier are fitted. The forks are of a new B.S.A. pattern provided with a tension spring and a shock absorber.

Handlebar and Tank.
The handlebar is of the adjustable touring type. The saddle type tank is supported by brackets on the frame ; the capacity being 1½ gals.

Wheels and Tyres.
The wheels have heavy gauge rims, size 19 in. x 2¼ in., enamelled. Dunlop cord wired-on 24 in. x 2.375 in. tyres are fitted, but 25 in. x 2.75 in. tyres can be fitted at a slight extra cost.

Brakes.
Two independently operated brakes acting in the same drum are mounted on the rear wheel. One being operated by the lever on the right of the handlebar, and the other by the heel pedal on the left side of the machine.

Saddle.
Best quality pan seat with leg springs. Spring seat saddle extra.

The machine comes well within the 30s. tax class.

Notes
1. More pages from this book are available at Craig Howell's Flickr pages. Craig Howell

Source: Book of the BSA by Waysider. Pitmans, 1928.