Description
10 Pages – PDF Download – Complete Series – Royal Enfield 250
“The ‘Hot’ 250
An anatomy of Enfield’s unit 250s, or the Crusader by any other name. Don Morley outlines the early history of the fast little singles before going on to describe the correct specifications and how to maintain them today.
Reg Thomas, who was royal Enfield’s chief designer, scooped the pool in more ways than one when he announced his all-new 250cc ‘Crusader’ model back in July 1956.
Not just because it was the first 1957 model to be announced in Britain but because here at last was a British motorcycle which had been designed afresh, almost literally from the ground up.
Mind you, never did any manufacturer more desperately need such an appealing product. Enfield’s 125cc ‘Flying Flea’ commuter bike had been an awful flop against BSA’s Bantam leaving Royal Enfield devoid of a small capacity bike for the volume market. Their 350cc Bullet was, in those days, considered a relatively small seller in the mould of BSA’s Gold Stars.
Faced with the urgent need to plug this market gap for RE, Thomas had, as a design starting point, latched on to Lucas’s latest alternator/generator electrical system. Indeed, from a clean piece of paper, he literally set to and drew a new engine around it.
His original ambition for the Crusader to be a luxury commuter went somewhat awry, for it actually evolved into a bike with far too much sporting potential.
Thomas reversed normal British practice by locating the engine’s timing gears, camshaft, oil pump and other parts on the nearside amidst the primary transmission. The electrics, unlike the similar unit construction BSAs and Triumphs, were built into the two compartments on the bike’s offside.
This meant they were surrounded by air rather than running in oil and did not have to put up with the non-stop barrage of steel particles being constantly worn off the clutch, sprockets and primary chain. Bikes like the Triumph Terrier or Cub and BSA’s later C15 or B40 used stators totally encapsulated to protect them from this. In fact, BSA/Triumph eventually copied Enfield’s arrangement for their 750cc triples…
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10 Pages – PDF Download – Complete Series – Royal Enfield 250
