Manx Grand Prix
History and Development
Consisting of a 1961 Manx Norton frame and Triumph Grand Prix motor (hence its ‘Manx Grand Prix’ name) the bike featured in and on the front cover of Classic Mechanics magazine, Spring 1985 issue. The owner Leslie Boustead recounted the story of how the machine came together as a collection of parts from various sources. When first constructed the ensemble’s main components consisted of the frame and engine plus a Triumph close-ratio gearbox, Norton short Road holder forks, Tickle alloy top yoke, BSA 190mm front brake with Dow Duetto tls conversion, Matchless G50 rear wheel, aluminium fuel tank and Ray Petty seat. The machine was built by John Gleed, at one time Eddie Dow’s service manager who supplied the Triumph engine and gearbox.

The engine consists of a Manx Grand Prix top end on a later (1957/58) and much stronger 650 bottom end with a one-piece, big-bearing crankshaft running shell big-ends. Other noteworthy features include a BTH racing magneto and twin Amal Type 6 carburettors fed by a central GP float chamber. The  machine features 4 leading shoe, Grimeca front brake and BSA conical-hub rear wheel. The Manx Grand Prix goes well and handles beautifully and has been photographed by hundreds of classic fans. 
Technical Specification
Engine              Triumph 6T/Grand Prix, four stroke twin air cooled
Capacity           498cc
Compression      9.5:1
Carburation        Twin Amal type 6
Ignition              BTH Racing magneto
Gearbox            4 speed close ratio
Clutch/drive       4 plate with Newby belt drive
Frame               Manx Norton M40
Suspension       Road holder forks with Manx springs and Hagon shocks
Brakes              Gremica 4LS and Triumph SLS
Tyres/wheels     Avon with 19" Akront rims
Top speed         100 plus
Construction      1983

Manx Grand Prix