Classic Bike (UK) - - Contents -

Nicksy on the decade when multi-en­gined mon­sters ripped up the drag strips


Of all the peo­ple who’ve done crazy things on mo­tor­cy­cles, the Top Fuel drag rac­ers of the 1970s rank sec­ond only to Isle of Man TT rac­ers in my books. The ’70s was a pe­riod of fran­tic tech­ni­cal change on the drag strips – twin-en­gined bikes pow­ered by Triumph and Nor­ton mo­tors were tus­sling for supremacy with a new wave of dou­ble-en­gined Har­leys, rear tyres were get­ting fat­ter, wheel­bases grow­ing longer and two- and three-speed trans­mis­sions had started to ap­pear.

The bikes were get­ting faster by the week – TC Chris­tensen achieved a ter­mi­nal speed of 180mph on his 1500cc dou­ble-en­gined Nor­ton, and the top con­tenders were vy­ing to set the world’s first seven-sec­ond mo­tor­cy­cle run.

I never got to see one of the big US bike drags in the ’70s, but at least I met the famed TC when he made a short Bri­tish tour. He named his bike Hogslayer be­cause it took over from Boris Mur­ray’s twin-en­gined Triumph as the most feared ma­chine in the USA, and con­sis­tently hum­bled the sin­gle-en­gined Har­leys.

That drove the Har­ley con­tin­gent back to sketch­ing on their Coors beer­mats, and the re­sult was the Har­ley dou­bles – W-fours, re­ally – and a flood of tum­bling elapsed times. TC’S fastest at that point was an 8.37sec run. Carl Ahlfeldt was field­ing the big­gest Har­ley dou­ble at 236 cu­bic inches (3.7 litres), but Joe Smith was the world’s fastest drag-bike rider at 8.201sec and a ter­mi­nal speed of 176.47mph on his 3700cc Har­ley. Com­ing up strongly was Russ Collins, who wedged three Honda CB750 en­gines into a mo­tor­cy­cle frame. With the ma­chine still in an early stage of de­vel­op­ment, he ran 8.47sec at 171.42mph. Danny John­son and Mar­ion Owens were other twin­harley ex­po­nents who were also run­ning in the 8.3sec bracket. TC and his en­gi­neer John Gre­gory, run­ning out of their Sun­set Mo­tors shop in Kenosha, Wis­con­sin, were un­der pres­sure. “I’ve got 300 horse­power in my Nor­ton and I can use it all,” he told me at the time of his Bri­tish visit. “The Har­leys are putting down about 400 horse­power and they’re only us­ing 70% of it. They can’t find the trac­tion to get all the power on the ground. They could be do­ing sevens now if they knew how to use the power.”

Rub­ber was as vi­tal to progress as horse­power. Tyre man­u­fac­turer M&H of­fered the quick­est rid­ers so many com­bi­na­tions of com­pound and sec­tion that “it would take me a year to test ’em all,” ac­cord­ing to TC. A six-inch rear tyre was the stan­dard size, but when M&H pro­duced an eight-inch rear, new chal­lenges arose. In the early de­vel­op­ment stages of the fat­ter tyre, only TC, Russ Collins and John­son used it.

The eight-incher, a two-ply de­sign, 28 inches in height, caused han­dling prob­lems for Collins and tossed TC onto the strip at 150mph, leav­ing him with cracked ribs, a crushed heel and calf and se­vere body abra­sions. He had been ex­per­i­ment­ing with dif­fer­ent tyre pres­sures, start­ing with 16psi and go­ing down in 2psi stages. At 8psi, the Nor­ton laid down on its side af­ter TC had com­pleted an 8.8sec run – the tyre walls had flexed too much. M&H re­sponded by work­ing on a four­ply ver­sion with a lower height – and by de­vel­op­ing a 10½in ver­sion. At the time of our meet­ing, TC was test­ing with M&H to de­velop this tyre, and was also tun­ing 850cc Com­mando en­gines and a three­speed trans­mis­sion, in an at­tempt to get back ahead of the Har­leys.

Not get­ting to see th­ese amaz­ing drag­bike wars in the US in the ’70s is one of the things I re­gret in life. I only read about it from afar, and sat en­thralled by TC’S tales. He and his clan were con­stantly push­ing tech­nol­ogy to the edge, never know­ing when some­thing was go­ing to break, with un­pre­dictable con­se­quences. They did it un­der the flood­lights, on a Satur­day night, the pits awash with eye­sting­ing ni­tro fumes and rag­ing ex­haust sounds. They did it with barely no man­u­fac­turer back­ing, and no one made se­ri­ous money out of it. True he­roes.

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