Frame

Numbered 64301 to 65745 (approx) Integral seat stays with cam type chainstays for rear wheel adjustment.

Wheels

WM1x21 (f), WM2x20 (r). Rear, QD with taper roller bearings. Chrome rims. Black spokes with NPB nipples. Rear sprocket integral with brake drum on LHS.

Mudguards

Plain inverted U section, unvalanced. Rear, two piece with detachable main section. Front & rear with flared ends.

Tanks

‘Aero’ type petrol tank chrome plated and painted panels with Enots reserve tap. Single central CEE-ESS type filler with rear fitted petrol balance pipe. Two bolt damper arm fixing. . Large cut aways underneath both sides to clear rocker box.

Engine

Numbered U2901 to U3200 (approx) - 4 valve 499cc with RR50 aluminium enclosed valve cylinder head (with 8 fixing bolts for rocker box), parallel inlet valves and radial exhaust. 14mm long reach central plug. BTH KD1 D4 magneto and DM3G dynamo. Oil feed to cylinder.

Brakes

8” front and 7.5” rear, coupled with aluminium shoes.

Electrics

Miller 8” headlamp with No 832 8-0-8 'Lighthouse' ammeter and 35E rear lamp. HF180 Clearhooter electric horn with Lucas LU76204 horn push. No stop light as standard.

Transmission

4 speed gearbox with foot change on RHS. Aluminium oil bath chaincase with ‘R’ on dome and no separate filler on shock absorber dome.

Carburetter

Amal type 29/146 or 229/146 with Binks twist grip control. Aluminium spacer to head. 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 illuminated speedometer. Lycett 6B pillion pad. Mechanism shield, battery cover, licence holder, cast central stand with lifting handle. 7/8” handlebars with long front brake lever. Single toolbox with screw fitting to lid fitted to RHS of machine. Steering damper and handwheel operated fork shock absorber. Round tubed forks. THAPEX tyre inflator. RH chainstay valence. Cover to front engine plates.

Extras

Upswept exhaust pipes. ISDT rear wheel. Blue or Maroon paint finish to mudguards and petrol tank.

Maintenance Data

  1. Magneto Advance BTDC - 12-14mm (39 to 42 degrees)
  2. Plug gap 0.012" to 0.015"
  3. Contact breaker gap 0.012"
  4. Tappet clearance (cold) -inlet, NIL, Exhaust 0.004"
  5. Piston ring gap 0.012"
  6. Oil capacity 1/2 gallon

 

©  Colin Chapple