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1930 Ulster Grand Prix


Numbered 36443 to 42995 (approx) Bolt on seat stays with drawback type chainstays for rear wheel adjustment..


WM1x21 (f), WM1x21 (r), interchangeable with black enamelled rims. Black spokes with NPB nipples. Bolt on rear sprocket.


Plain inverted 6” U section, both unvalanced. Rear with detachable tail piece.


Petrol tank black with gold lined panels. Single offset Westwood type filler with front fitted petrol balance pipe. Single bolt damper arm fixing and side cut away for sparking plug access. Brass lever petrol tap.  Oval 'Rudge-Whitworth' rubber gnee grips. Rounded oil tank mounted on seat tube with single Westwood type filler to offside.


Numbered 1 to 5100 - 4 valve 499cc with iron open valve parallel inlet & parallel exhaust cylinder head. Rockers carried on cast pillars. 18mm central plug. Forward mounted  type F 6V ML Maglita or round ML magneto. Round based cylinder barrel and webbed (6) drive side crankcase. Timing side crankcase with ‘Rudge Whitworth’ cast in. (note that early crankcases did not have the ‘Rudge Whitworth’ cast in). Cast alloy oblong rocker cover with ‘R-W’ cast in. Oil feed to rear of cylinder.


8” front and rear, coupled with steel shoes.

Electrics (optional)

Miller 7” headlamp (bayonet fitting rim) with No 74E 6-0-6 'Lighthouse' ammeter  and 34E rear lamp.


4 speed semi close ratio gearbox with hand change on RHS. Aluminium non-oil bath chain cover with aluminium chainguard. ‘Rudge Whitworth’ cast into gearbox quadrant cover.


Amal type 29/105 with 2 lever control (optional twist grip). Smiths Petroflex fuel line. Air intake bellmouth with flame trap (gauze) (M2853 x 6)

Exhaust system

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

Standard Fittings

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


Chromium plated tank with black or maroon panels. Nickel plated tank with black or maroon top and side panels. Maroon panelled tank and mudguards. Bonniksen trip/non trip internal drive speedometer. Time speed meter. Guaranteed 90MPH (£75)  and 100MPH(£85). WM2x21” or WM3x19” wheels.

© Colin Chapple


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©  Colin Chapple