Formed in the 1880’s in Fitchburg, Massachusetts, Iver Johnson Company built bicycles, firearms and by 1911, motorcycles. Not satisfied to follow other makers, stating a goal of “mechanical perfection,” innovative design and manufacturing techniques show in their motorcycles including this single-speed 1915 twin.
While a visit to the Museum would allow you to kneel next to this machine, feast your eyes on the Iver Johnson’s great details, we hope these photos will help. To begin with, the overall lines of the bike are unique. Iver Johnson used on some of their bicycles the “truss bridge” frame design, and used it on motorcycles as well. The sweeping fuel tank form is complimented by the rakish handle bar, a deep V form when viewed from above. Following the line of the handle bar, the leading link “girder” fork incorporates a delicate multi-leaf spring, nickel plated as are many detail parts on the Iver Johnson.
Hidden inside the gleaming nickel plated motor is a unique planetary gear driven “cam” to open and close the valves. An original factory drawing is included here to explain. Roller tappets ride on the outer surface of the large gear, so no actual “camshaft” is used. Also inside the engine, unique for the time, is a double pin crankshaft. Iver Johnson engineers felt that for optimal balance and smoothness the pistons should reach the tops of their cylinders simultaneously. Also, the engine served as a “stressed member” as the frame is open at the bottom. (For the two-speed V-Twin versions, a unique in-unit planetary gear setup was employed. But in use this transmission could not withstand the engine’s power. The company switched to a sourced two-speed rear hub arrangement for their two-speed twins.)
Patrick Simmons, singer and guitar player for the Doobie Brothers, was lucky enough to be high bidder at the E.J. Cole auction in 2015, and has this to say about his Iver Johnson; “I have always loved the design of these motorcycles, from the shape of the gas tank and frame, beautiful fork castings, well crafted leading link/leaf spring suspension, and most interesting, the offset crank pin design, which as far as I know, is the only example of this technology in this pre-World War I era. The gray, black, and white paint scheme, with the gold, and red lettering has so much aesthetic appeal for me personally. And the beautifully nickeled motor and quality mechanical castings make this one of the most beautiful motorcycles ever made.” Our thanks to Pat for offering his Iver Johnson on loan to the Museum for visitors to enjoy. With only a few still in existence it’s a real treat to see one.
- Engine: Side-Valve V-Twin
- Displacement: 62 Cubic Inch/1020cc’s
- Ignition: Magneto
- Horsepower: 7.5
- Valve Actuation: Planetary Gear Driven Cam
- Starting: Pedal Crank/Valve Lifter
- Primary: Direct to Clutch
- Transmission: Single Speed/Clutch