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1931 Special


Numbered 42996 to 46500 (approx). Bolt on seat stays with cam type chainstays for rear wheel adjustment.


WM2x19 (f), WM2x19 (r). interchangeable with black enamelled rims. Black spokes with NPB nipples. Bolt on rear sprocket.


Inverted 5 1/2” U section, unvalanced, front and rear. Rear with hinged tail section.


Petrol tank chrome plated with lined black panels. Single offset CEE-ESS type filler with front fitted petrol balance pipe. Single bolt damper arm fixing. Brass lever petrol tap. Oval 'Rudge-Whitworth' rubber gnee grips.


Numbered 1 to 4900 (approx) - 4 valve 499cc with cast iron open valve cylinder head, parallel inlet valves and parallel exhaust. Rockers carried on cast pillars.18mm side plug. Carburetter flange sits proud of cylinder head finning. Rear mounted round CMAK ML magneto and forward mounted short  Miller DM3G dynamo (when lights fitted). Oil feed to rear of cylinder. Cast oblong plain rocker box.


8” front and rear, coupled with steel shoes.

Electrics (optional)

Miller 7” headlamp (bayonet fitting rim) with No 74E or later No 75 6-0-6 'Lighthouse' ammeter (illuminated) and 34E (early models), 39E or 39ER (latest models) rear lamp. Later machines used the No 74ES headlamp with the clip fitting rim. DM3G dynamo.


4 speed gearbox with hand change on RHS of tank. Steel open backed primary chain cover with an identical aluminium version being introduced for later production machines. Steel rear chain guard.


Amal type 6/141 long body with Amal straight pull twist grip control. Original settings: main jet 150, slide 6/4, needle jet 106, needle position 2. Chrome plated copper fuel pipe.

Exhaust system

Twin 1 3/4” low-level downpipes into Rudge ‘can’ type silencers and 6” fishtails.

Standard Fittings

Rear carrier (at no extra charge), 1” handlebars with folded type inverted levers and steering damper. Single toolbox fitted to offside of machine. Spanner adjusted fork shock absorber. Pressed steel centre stand. Open ended ‘D’ section forks.


Chrome plated petrol tank with black or maroon panels and black with maroon guards & tank panels. Smith’s trip/non trip speedometer, Smith’s 2"  (2.4" diameter)  8 day clock in damper arm, Bonniksen speedometer, legshields, electric horn and Lucas No 63 bulb horn. Optional 2 lever control to carburetter.

© Colin Chapple


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©  Colin Chapple