Frame

Numbered 55701 to 58075 (approx). Integral seat stays with cam type chainstays for rear wheel adjustment.

Wheels

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

Mudguards

Plain inverted U section, unvalanced. Rear with detachable main section. Front & rear with flared end.

Tanks

‘Aero’ petrol tank painted with lined panels with Enots reserve tap. Single central CEE-ESS type filler with front fitted petrol balance pipe. Two bolt damper arm fixing. Cut out under the tank for access to the sparking plug.

Engine

Numbered U1001 to U1600 (approx) - 4 valve 499cc with aluminium bronze open valve cylinder head, parallel inlet valves and radial exhaust. 14mm central plug. BTH KD1 D4 magneto and DM3G dynamo. Oil feed to rear of cylinder. Cast alloy rocker cover with cast ’R’ motif.

Brakes

8” front and rear, coupled with aluminium shoes.

Electrics

Miller 8” headlamp with No 832 8-0-8 'Lighthouse' ammeter and 29E rear lamp. Lucas HF1140 (chrome tone disc nut & polished tone disc) electric horn mounted on special frame lug on rear downtube. Lucas LU76204A horn push

Transmission

4 speed gearbox with foot change on LHS. Aluminium oil bath chaincase with ‘R’ on dome and separate filler on shock absorber dome.

Carburetter

Amal type 29/146 with Binks twist grip control. Original settings: Main jet 160, slide 29/5, needle jet 109, needle position 3. Smiths Petroflex fuel line.

Exhaust system

Twin 1 3/4"” low-level downpipes into barrel silencers and plain tailpipes.

Standard Fittings

120MPH trip speedometer and matching ‘Revulator’. Mechanism shield, battery cover, licence holder, Cast central stand with lifting handle. 1” handlebars with long front brake lever. Two toolboxes fitted to either side of machine. Steering damper and handwheel operated fork shock absorber. Lycett No 6B pillion pad. Round tubed forks. THAPEX tyre inflator. Sorbo knee pads to rear of saddle. RH chainstay valence. Cover to front engine plates.

Extras

Upswept exhaust pipes, pillion footrests, Rudge quickly detachable and interchangeable wheel on Watsonian or Swallow sidecar.

©  Colin Chapple