The Harley-Davidson X-90 Shortster was offered in America for three model years, 1973-1975 and records show about 17,000 of the Italian-made minis were sold. With 10 inch wheels, a four speed transmission, wet multi-plate clutch and an 8 horsepower two-stroke engine it was more sophisticated than many American minis from the 1960’s like those from Fox and Rupp.

The X-90 Shortster uses a solid backbone-style frame, hydraulic suspension, street legal lighting, a license plate mount, gauges and a braced handlebar that can be folded for transport. Picking up on styling trends, the bike incorporated an upswept exhaust with a chrome heat shield, a solo seat, big bike grips, polished stainless steel fenders. Blue and red machines are noted to have been made, but black seems the most common color, with classic AMF graphics applied. The wheelbase was just over 40 inches and tires were a healthy 3.00 x 10 inches. The X-90 was derived from the MC-65 and replaced it in the Harley lineup, but there is almost no parts interchangeability between the two machines.

Harley-Davidson’s partial ownership of the large Italian manufacturer Aermacchi brought a wide range of street, racing and off-road motorcycles to showrooms. In 1960, well before the Japanese Big Four had penetrated the U.S. market, Harley-Davidson had purchased a 50% share, and in 1974 owned Aermacchi completely. Harley already had American-made lightweight two-stroke bikes like the Hummer, 165 and Scat plus their Topper scooter, but the Aermacchi relationship brought more lightweight machines helping dealers match the offerings of the competition. Through this Italian connection updates also came at a more rapid pace.

When you visit the National Motorcycle Museum you can see the X-90 Shortster as well as an example of its predecessor, the MC-65 and other scooters and minibikes from France, Germany, Japan, Italy and of course the United States. This X-90 Shortster is graciously on loan to The National Motorcycle Museum from Peter Cook of Florida.


    • Engine: Two-Stroke Piston Port Single
    • Bore & Stroke: 48mm x 50mm
    • Displacement: 90.5cc’s
    • Carburetion: Dell’Orto SH2/20
    • Electrics: 6 Volt Battery, Coil & Points
    • Compression Ratio: 8.5:1
    • Lubrication: Oil-Injection
    • Primary: Helical Gear Driven
    • Starting: Kick Lever
    • Transmission: 4-Speed, Foot Shift
    • Clutch: Wet, Hand Operated
    • Final Drive: Chain
    • Brakes: Drum Front & Drum Rear
    • Frame: Steel Tubular, Backbone
17 replies
  1. Michael vincent
    Michael vincent says:

    I had one like the blk one I traded my Honda 50 a 1969, it was not a good trade, my h.d. 90 was in need of work witch I did at 12 yrs old np I got it going great, but the shifter on mine was so strange it had linkage from the shift arm but the main connection was on top of motor mmine striped it was sixty bucks in77, I put vice grips on it so tight I was able to reach with foot and shift. It was were the clutch cconnects on the one shown. The most rediculus engineering. But I love d it four speed I was keeping up with the rm yz, anyone saw this shift crazyness I’m talking. Ty boys

  2. Robert Wakeman
    Robert Wakeman says:

    I have a 1973 Harley Davidson x90 shortster was in my uncle’s basement for over 20 years left clutch handles missing front wheel is really rotted out everything is locked up but all original good paint I’m willing to sell it to the right person needs work but if you know about these bikes you know what they’re worth I left my email wakr 750 at gmail.com

  3. Jaime
    Jaime says:

    I have a1973 Harley-Davidson x90 running in better then good condition I just rode it 12 miles with no problem and I have paper work to go with it anyone interested make me a good offer before I start a restoration job on it

  4. Jaime
    Jaime says:

    I have a1973x90 in good condition just rode it 12 miles with no problem was gonna restore but before I get started if anyone is interested in buying make me a offer and comes with paper work pink slip and possibly owners Manuel I can be reached at


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