Frame

Numbered 49601 to 52195 (approx). Bolt on seat stays with cam type chainstays for rear wheel adjustment. Some frames had 8 bolt fixing for the petrol tank, others 4 with the outer 4 fixings crudely sawn off.

Wheels

WM1x21 (f), WM2x20 (r). Chrome rims. Black spokes with NPB nipples. Bolt on rear sprocket.

Mudguards

Plain inverted U section, valanced front with no splashguard. Rear with hinged tail piece.

Tanks

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 and side cut away for sparking plug access. Some tanks were 8 bolt fixing. Brass lever petrol tap.

Engine

Numbered 1 to 450 (approx) - 4 valve 499cc with iron open valve cylinder head, parallel inlet valves and radial exhaust. 18mm central plug. TT Replica type crankshaft and cylinder barrel. Webbed drive side crankcase (8) and single web under timing cover. Front mounted BTH mag generator type PBK1 Form R or BTH magneto (where no lights fitted). Oil feed to rear of cylinder. Plain cast alloy rocker cover.

Brakes

8” front and rear, coupled with steel shoes.

Electrics (optional)

Miller 7” headlamp with No 832 8-0-8 'Lighthouse' ammeter and 29E rear lamp. Stop lamp.

Transmission

4 speed semi close ratio gearbox with foot change on LHS. Aluminium oil bath chaincase with no ‘R’ on dome and separate filler on shock absorber dome. (no forward extension for dynamo).

Carburetter

Amal type 29/005 with Binks twist grip control. Original settings: Main jet 170, slide 29/5, needle jet 109, needle position 3. Smiths Petroflex fuel line.

Exhaust system

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

Standard Fittings

Pressed steel central stand with lifting handle. 1” TT pattern handlebars with folded type inverted levers & clutch lever. Single toolbox fitted to offside of machine. Steering damper and fork shock absorber with handwheel. Open ended ‘D’ section forks with rubber buffers to rear of fork bridge.

Extras

Smiths 2" 8 day clock in steering damper arm, pillion footrests, leg shields, Smiths or Bonniksen speedometer, competition exhaust pipes, electric horn, Lucas No 63 bulb horn. Black & gold or chrome plated petrol tank with maroon panels with black or maroon guards. Black with maroon guards & tank panels.

©  Colin Chapple