EXCELSIOR

250 Manxman - 1937

A very special 250 racer

Unlike its predecessor, the famous four-valve "Mechanical Marvel" of 1933, the Excelsior Manxman never achieved the supreme honor of victory in the Isle of Man TT. Nevertheless, it was the most successful 250 racer of its day. This particular Manxman – one of six works bikes built with plunger rear suspension – was ridden to victory by the amateur Denis Parkinson in the September 1937, Isle of Man "Clubman" Manx Grand Prix.

New Lap Record

Parkinson finished ahead of such rivals as Rudge and OK Supreme and established a new lap record of 71.3 mph. A similar bike, ridden by Ginger Wood, finished second in the 1938 Lightweight TT behind the supercharged DKW of Ewald Kluge.

Delivered Ready to Race

Its shaft-driven overhead-camshaft engine was designed by Ike Hatch and built by Blackburne. The first Manxman appeared in 1935 and formed the basis for a "client competition" machine that the catalog proudly claimed was not a replica but a real purpose-built track machine delivered ready to race. Nevertheless, there were major differences compared with the works racers. Parkinson's machine had only the dual seat in common with the "client competition" machine. Its engine casings were cast from magnesium, the gearbox was bolted in unit with the engine and the rear suspension (standard racers had rigid frames) had adjustable springing and damping. The works Manxman also served as a test for the radical Girling drum brakes.

SPECIFICATIONS

Engine: 249cc (67x70.7mm) air-cooled single-cylinder four-stroke; aluminum-bronze cylinder head.

Valves: overhead-camshaft; enclosed hairpin valve springs

Fuel System: Amal carburetor

Transmission: 4-speed, chain final drive

Suspension: girder forks (front); plunger (rear)

Brakes: Girling drum (front & rear)

Wheels: 2.75x21 inch (front); 3.00x20 inch (rear)

This 250 Manxman was one of six built with a plunger frame.