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Excelsior 500cc G15 Manxman Special OHC


ENGINE - Excelsior Special Overhead Camshaft Engine of advanced design, built throughout to give highest possible efficiency and maximum power output incorporating Special Bronze Head, Special Hardened Iron Alloy Cylinder. Racing Valves and Springs, and many successful features developed during two seasons racing.

All internal parts are especially strong and massive ; Bore & Stroke, 498 c.c. - 82 m m. x 94 m m.

Crank shaft is mounted on Special Hoffman double row roller bearings on drive side and ball bearings on the timing side. Crank pin of 1.4" diameter has double row caged roller bearings.

Flywheels which are integral with the main shafts of l 1/8" diameter are made from high tensile steel forging. Con-rod is of special alloy of immense strength.

Piston is three-ring slipper type, hollow gudgeon pin is 7/8" diameter.

Camshaft drive is arranged with bevels of case hardened steel gears, the hunting tooth principle being incorporated to eliminate excessive wear of gear wheels.

Vertical shaft is 3/4" diameter mounted on four bearings with specially ground Oldham Couplings at top and bottom.

CAMSHAFT runs on THREE BEARINGS, the cams being fitted on a taper and easily removable.

ROCKER SHAFTS are mounted in substantial bronze bushes in camshaft housing.

ROCKER BEARINGS are floating bushes and needle rollers on hardened steel shafts. Exhaust and inlet VALVE GUIDES are bronze in both cases.

LUBRICATION - Dry sump lubrication carried out by two gear pumps which are kept primed under all conditions. The feed pump forces oil to the big end and cylinder head camshaft assembly. The head is completely drained on stopping the engine and all surplus oil passes down the vertical shaft tunnel to the enlarged double sump in the special alloy crank case.

FRAME - Entirely new type cradle frame constructed of large diameter tubes of exceptional strength ensuring perfect steering and absolute rigidity at high speeds. Sidecar lugs incorporated in frame.

FORKS - Genuine T.T. forks with taper tubes and large steering damper and shock absorbers.

GEARBOX - Heavyweight Four-Speed, with enclosed positive change Foot Control and cork clutch running in oil. Foot change lever mounted on splined shaft readily adjustable for position.

TANK - Large Welded steel saddle tank, chromium plated, with red side panels (black enamel tank optional). Capacity 3A gallons. Oil tank mounted on seat down tube. Capacity eight pints. Both tanks fitted with quick action hinged filler caps.

CARBURETTER - Large bore T.T. 35 " AMAL," with downswept intake operated by quick action twist grip.

WHEELS and TYRES - Built up with 7" forged steel hubs and high tensile steel axles, with journal Bearings to both wheels. DUNLOP CORD Tyres, 27" x 3" ribbed front, and 26" x 3.50" studded rear.

BRAKES - internal expanding with finger adjustment, 7" diameter front and rear with forged steel drums and 1 1/4" wide Special Alloy, Genuine T.T. Brake shoes.

TRANSMISSION - Totally enclosed front 1/2" x .305" chain in Cast Aluminium Oilbath case. Rear chain - 3/8" x 1/4" with top half chain cover and positively lubricated.

MUDGUARDS - Strong ribbed section steel guards with hinged rear to facilitate wheel removal.

HANDLEBARS - Adjustable with Forged Steel external levers and separate adjustments.

IGNITION and LIGHTING - Miller 6 Volt Dyno-Mag. (combined dynamo and magneto with detachable dynamo portion) equipped with quickly detachable 8" headlamp and instrument panel in tank.

SILENCER - Downswept pipe with megaphone type silencer having instantly detachable baffles. (Upswept pipe optional). TOOLBOX and EQUIPMENT - Shaped metal toolbox with separate compartment concealing accumulator. Full sec of tools. Electric Horn, Licence Holder, Prop Stand and Mud- guard Pad.

WEIGHT - In Touring trim with lighting set : 350 lbs. Approx.

500 c.c. Model G.I5
Code Word : " MANXIL "


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