Restoration guide | Expert advice
Triumph Model H The specialisTs There is no specific club for the Model H, but the Vintage Motor Cycle Club is an obvious port of call for the would-be restorer as the club has a marque specialist for the early Triumphs. Our specialist this issue, who prefers to remain anonymous, advises that as the model celebrates its centenary in 2015, the occasion may be marked elsewhere, as well as a definite event in Cumbria in the summer. Veteran Triumph Spares (www.parts@veterantriumph.co.uk) is a useful source
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model hisTory
The Model H is often known as the ‘Trusty’ Triumph, although the alliteration had long been applied to earlier models. Triumph claimed the H was a virtually new design but, in reality, it was an evolution of the Model A. The most important feature was the transmission. Rather than a belt direct from crankshaft to rear wheel pulley, the H used a countershaft gearbox. It was the final link that defined modern motorcycles from the evolutionary veterans. Although the 1915 launch date appeared less than auspicious, the First World War was still getting into its murderous stride and civilian motorcycle trade continued until mid-1916. In spite of Triumph’s strong German connections, around 30,000 Model Hs were supplied for military service. Postwar, some WD bikes returned to the factory, where they were completely overhauled and sold into the civilian market. There was no mis-representation, even the tank badges declared ‘Renovated.’ Consequently, many motorcycles ended up with mixed identities. Complete new machines were also available. While the years of manufacture of engines, frames, gearboxes etc can be determined, the total number of Model Hs built remains something of a mystery, although some sources quote 57,000. By 1920, Triumph offered the SD with chain final drive, the following year the overheadvalve Ricardo. Perhaps that ‘Trusty’ reputation ensured the increasingly anachronistic H was offered until 1923.
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Words: ALAN TURNER
Engine A welcome part of the ‘Trusty’ legend is that the engine has no inherent faults. e sidevalve unit combined a bore of 85mm with a stroke of 97mm for 550cc. e barrel and head were one casting, with caps covering the equal-sized valves. Although officially rated at 4hp, the manufacturer tempted: ‘developing considerably more under favourable conditions’. e crankshaft turned on ball bearings, the big-end used a roller bearing. is was another significant advance in
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engine design. A single camshaft operated the valves via rockers and clearances were achieved with adjustable tappets. An extra camshaft ramp operated the decompressor, which acted on the exhaust valve when operated by a small foot pedal. A small Renold chain drove the magneto. e carburettor was of Triumph’s manufacture. Restorers of early machines usually assume their projects have zero parts availability. e Model H offers a pleasant surprise in that Veteran Triumph Spares carry quite a
The ClassiC MoTorCyCle | MAY 2015
selection of parts. Among the many consumables listed there are pistons and rings permitting straightforward rebores. Searching for engine castings will involve jumbling and Google-gazing, but patience should be rewarded sooner rather than later. While Triumph may have introduced some updates, all the parts, 1915-23, remained interchangeable. 02
Transmission Beneath an alloy cover, a primary chain (Renold originally) transfers drive
to the four-plate clutch. Veteran Triumph Spares can help with many parts. e drivetrain continues to the Sturmey-Archer three-speed unit; this set the Model H apart from other bikes. e gears were in constant mesh and the factory claimed the design even allowed clutchless gear changes, achieved by a sturdy hand lever pivoting on the frame’s saddle tube. Another improvement was a kickstart to bring the engine to life. Gearbox lubrication required the regular application of an oil gun. Provided there has been some effort with the
slippery stuff, the gearbox is long lasting and gives very little trouble. SturmeyArcher parts can still be found. e final drive was by V-belt, still obtainable from various manufacturers and in different materials. Each will have proponents and opponents. It seems there’s an ideal combination for every bike – it’s just a question of finding it. 03
Electrics e first Model Hs were fitted with ML PM1 magnetos, exact copies of the Bosch ZE1,