The name “Barn Job” suggests something cobbled together, which this Vincent definitely was not. With it, builder/rider Clem Johnson would become the first drag bike racer to go 140, 150 and 160 mph. For more than five years, the machine held the record for both elapsed time and top speed. Its quickest would be 9.70 seconds; its fastest was 151.51 mph.
The only things “Vincent” about the engine were the crankcases and timing covers. Johnson and partner Ralph Owen made everything else. The flywheels were fashioned from mild carbon steel and helped increase displacement from 61 to 96 cubic inches. Pistons were machined from forged aluminum billets; intake valves enlarged by turning down items from a Mack truck; and pushrods made from C-1144 steel.
Although Johnson rode the machine for many years, he later turned that responsibility over to Jim Leineweber (who would go on to become one of the premier manufacturers of motorcycle camshafts) “The only difference between Jimmy and I is that I get nervous and he doesn’t,” said Johnson.
While all of the top racers were by definition enormously talented, CLEM JOHNSON is generally recognized as one of the most talented of all. Not only was he a brilliant craftsman, his machine is a true work of art.

  • Engine: 1600cc Vincent
  • Carburetion: Hilborn injectors
  • Clutch: Johnson-developed clutch with Harley-Davidson components
  • Frame: Custom made of aluminum
  • Front end: 32mm Ceriani road race
6 replies
  1. Mike Hernandez
    Mike Hernandez says:

    Clem was a great person. As a kid, he hired me to mow his lawn and clean his pool. That was in late 60’s early 70’s in West Covina on Orange Ave. We lived next door. He helped us put in a gate between properties and he let us use his pool anytime we wanted to. His garage was his shop. It was always so sparkling clean and very neat. I got to watch him race one time. He invited me to go.


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