1947 Harley-Davidson Knucklehead EL Sidecar Rig

Except for their limited production racing machines, at the beginning, Harley-Davidson built only inlet-over-exhaust and then side-valve powered motorcycles for a little over twenty years. They first experimented with overhead valve engines in smaller single-cylinder bikes like the BA; this 350cc single with an exposed valve train was popular in export markets.

But in 1936 dealers and customers welcomed their first big twin overhead valve bike. Considered more efficient and durable, the 61 cubic inch EL and later 74 cubic inch FL had remarkable styling; to this day the Pre-War ELs and FLs are widely appreciated.

How did the new big twin work? By comparison, most records show a 1917 J model produced about 16HP, a JD about 24HP, the JDH about 29HP, the VL about 30HP. But the first EL was up to 40 horsepower. Of course, in that time the bike’s weight went from about 350 pounds to 565 for that 1936 EL, or Knucklehead as they became known decades later. Still, American riders craved the torque and the highway-ready massiveness of this machine, great for two-up riding or pulling a sidecar. In general, today’s big twin Harley-Davidsons have quite a bit in common with the original EL, and changes were gradual.

This fine Harley-Davidson Knucklehead sidecar rig will be among hundreds of motorcycles and thousands of pieces of memorabilia offered in the John Parham Estate Collection Mecum Auction at the National Motorcycle Museum, Anamosa, Iowa, September 6 – 9, 2023. Watch for information on the Mecum Auctions website,  Mecum.com  For schedule information or to register as a bidder for this and all Mecum events, visit Mecum.com, or call (262) 275-5050 for more information.

Specifications:

• • Engine: 45 Degree V-Twin
  • Type: Overhead Valve, Air-Cooled
  • Displacement: 61 Cubic Inches/ 988cc’s
  • Bore & Stroke: 3.31″ x 3.50″
  • Compression Ratio: 7: 1
  • Horsepower: 40HP
  • Carburetion: 1.25″ Linkert
  • Primary: Chain
  • Transmission: 4-Speed, Hand Shift/Foot Clutch
  • Final Drive: Chain
  • Brakes: Drum, Front & Rear
  • Electrics: 6 Volt Battery, Coil & Points
  • Frame: Steel /Double Down Tubes
  • Fork: Springer/Oval Tubing
  • Rear: Rigid, Sprung Seat
  • Wheels/Tires: 5.00″ x 16″ / 5.00” x 16″
  • Wheelbase: 59.5 Inches
  • Weight: 565 Pounds
  • Top Speed: 95mph (Solo Bike)