The Tonkin Tornado: A Street-Legal Norton Manx

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The Tonkin Tornado - Steve Tonkin's custom-made, street-legal Norton Manx.
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Steve Tonkin's custom-made, street-legal Norton Manx features specially made primary case houses an alternator and belt-driven dry clutch.
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Steve Tonkin's custom-made, street-legal Norton Manx.
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Finished in the classic Norton colors of silver with black and red pinstriping, Steve Tonkin's custom-made, street-legal Norton Manx is the ultimate back road burner — effectively a racer with lights.

“Tonkin Tornado” Street-Legal Norton Manx
Claimed power: 50hp @ 7,000rpm
Top speed: 130mph
Engine: 500cc DOHC air-cooled single, 86mm x 85.8mm bore and stroke, 9.5:1 compression ratio
Weight: 322lb (146kg)
Fuel capacity/MPG: 3gal (11.3ltr)
Price: Around £33,000 (approx. $53,000)

One of the most famous British motorcycles of all time, the Norton Manx is among the most sought after and highly regarded race bikes ever made. Fast and light, beautiful to look at and to hear, Norton Manxes powered a legion of riders to podium finishes for almost a quarter century.

Read about the history of the featherbed Norton Manx

They also fueled a legion of dreams. Just about every classic bike enthusiast, we’d wager, has dreamed of owning a Norton Manx. But not necessarily a full-on racer. Rather, one modified for daily service, tamed just enough to be used legally on public roads. It would be the ultimate café racer.

Many have dreamed the dream, but few have lived it. Steve Tonkin, 1981 Isle of Man TT 250 Junior winner and full-time classic bike restorer and builder, has made the dream come true for one very lucky man with his most recent build a street-legal Norton Manx he calls the Tonkin Tornado.

“I was talking to my friend William McRobie about my plan to build a Manx Norton that was road legal,” Steve explains. “There have been Manx-based road bikes before, but they have usually been lash-ups — worn-out old racers with a silencer instead of a megaphone and a registration plate stuck on the back. Nobody had done it properly.” Steve’s creation was going to be brand new and have lights and a kickstart — this would be one Manx that you wouldn’t have to bump start. “I wanted a challenge, and when I explained what I wanted to do, Mac [McRobie] said that if I would build it, he would buy it.”

The result is the bike you see here — the Tonkin Tornado. Powered by a 500cc Molnar Manx engine built to 1961 specifications, it will do 140mph on Isle of Man gearing, but Steve has fitted a smaller, 19-tooth gearbox sprocket instead of a 21-tooth so the Manx maxes out at 115. “Sacrificing a little bit at the top end makes sense if you want to ride on the road,” Steve tells me before we set off for a test ride. “You can still cruise all day at 100, but if you want more speed then swapping sprockets and the chain won’t take long.” MC

Read more about Steve Tonkin and his street-legal Norton Manx in the November/December 2011 issue of Motorcycle Classics. Call Customer Service at (800) 880-7567 or contact us by email.


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