1951 Series C Black Shadow

Enthralled by a Vincent

By Greg Williams
Updated on October 10, 2025
article image
by Kurtis Kristianson

1951 Series C Black Shadow

  • Engine: 998cc OHV air-cooled V-twin, 84mm x 90mm bore/stroke, 55hp @ 5,700rpm stock, w/7.3:1 compression ratio. (Horsepower now unknown w/8.5:1 compression ratio)
  • Top Speed: 125mph (est.)
  • Carburetion: 2 Amal 1.125in 289 Pre-Monobloc
  • Transmission: 4-speed, triplex chain primary drive
  • Electrics: Lucas KVF magneto, Miller 6V dynamo
  • Frame/wheelbase: Single upper frame member, stressed engine, 56.5in (1435mm)
  • Suspension: Girdraulic front, dual spring/single shock triangulated swingarm rear
  • Brakes: Dual drum 7in (178mm) front, drum 7in (178mm) rear
  • Tires: Avon Speedmaster MKII 3.00 x 20in front, Avon SM MKII 3.50 x 19in rear
  • Weight: 458lb (207.75kg) dry
  • Seat height: 32.5in (825.5mm)
  • Fuel capacity: 4.2gal U.S. (15.9ltr)

After cleaning up some wiring to the headlight of his 1951 Series C Vincent Black Shadow, Howard Smith headed out for a quick test ride on a nearby country road. He hadn’t owned the bike, which he had purchased in 1993, for very long.

“Things seemed to be working right,” he explains. “But I was riding along with one hand on the throttle and with the other, I was messing with the headlight switch to see what kind of readings I was getting on the amp gauge. Of course, I was wearing jeans and a T-shirt, and I hit a deep dip in the road, and the front (Girdraulic fork) totally unloaded. I was going about 60 or 65mph, and it went into a lock-to-lock tank slapper that lasted all of two seconds. The front tire got enough grip to somersault the bike, launching me in a wide arc onto the road where I flailed along like a rag doll.”

He continues, “I wound up sliding on my back into the grass of the opposite ditch while the bike gyrated end over end beside me. I was hoping it wouldn’t land on me, and it came to rest in the middle of the road, still running, with fuel pouring out of the tank.”

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