AMF Harley-Davidson X-90 (MiniBike) Page 1 of 2

data sheet:

Years built: 1973, 1974 and 1975
Bikes produced: 8250 bikes for 1973, 7019 bikes for 1974 and 1568 bikes for 1975
Price in 1973: 2456 francs T.T.C (in France)
Vehicle Ident. # (VIN): 2D
Spark Plug: HD 5R6A
Gas Capacity:  
Transmission: 4-Speed
Carburetor: Dell Orto SH2/20
Electrical System: 6 Volt
Saddle Height: ???


Model designation letter: X
Type: 2 cycle, single cylinder, 90,43ccm, air cooled
Bore: 48 mm (1.89 inches)
Stroke: 50 mm (1.97 inches)
Piston displacement: 90,43 ccm
Compression ratio: 9.2: 1
Lubrication system: Fuel and oil mixture
Starter system: Primary kick

Dimensions and Weight

Overall length: 145 cm
Handlebar width: 84 cm
Ground clearance: 15 cm (5.9 inches)
Wheelbase: 40.7 inches
Seats: 1 person
Front suspension: Telescopic oil dampened, three different types over the year: Cerrani, Marzocchi, Betor
Rear suspension: Swinging arm, oil dampened;
Fuel tank: 5,3 litres (1.4 gallons) Total
Transmission: 1,37 litres (1 quart)
Front fork: 28 mm diameter (Marzocchi), 150ccm each side (See page 2 for more details!)

Transmission System:

Clutch: wet, multi plate
Gear ratios: 1st: 20,06, 2nd: 11,23, 3rd: 7,38, 4th 5,77
Gearshift pattern: 1 down - 3up

Wheels and Brakes

Front wheel tire: 3.00 x 10 (Pirelli MT 74)
Rear wheel tire: 3.00 x 10 (Pirelli MT 74)
Front brake: internal expanding
Rear brake: internal expanding
Rims (Front & Rear): Disc Wheel, WM1= 1.6x 10"
Tire pressure (Front): 18 PSI
Tire pressure (Rear): 22 PSI

The X-90 was sold as 1973-1975 model years. The production year and model year are not always identical.
The minibike
was available in three different colors:

  • black
  • sparkling red
  • sparkling blue

Only the gas tank was painted, the fenders were always raw stainless steal. the decal design changend on every model year.
The color of the frame was always black
. The decals were on top of the paint without any clear coat to protect them.

The bike had been available in black or sparkling blue only. So far I never have seen a 1973 model year with a "sparkling red" gas tank. I assume this color was introduced with the 1974 model year.
Early "sparkling blue" gas tanks had longer silver stripes than later versions of the bike (about the same size as the "AMF Harley-Davidson" decal). At some point in production they changed this to shorter stripes. The stripes on black gas tanks had three different colors: red, blue, white.

  • 11 stripes on top (red on black gas-tanks)
  • 3 stripes over the "AMF Harley-Davidson" decal (white on black gas-tanks)
  • 4 below the "AMF Harley-Davidson" (blue on black gas-tanks).
  • On sparkling blue gas tanks all stripes were silver.

If you need gas-tank decals for your X-90, please feel free to contact me, I may help you there!

The X90 replaced the earlier Shortster (MC-65) which was available in 1972 only.
One of the innovations on the X-90 compared to it's predecessor was the fold down handlebar which made it easier to transport the bike.
For some the X-90 may seem very similar to the shortster, but it is a complete different bike. For example: Frame, Front Fork, Rear Fork, Gas Tank, Engine and Exhaust are different from Shortster.
The engine used in the X-90 is the same as used on the Z-90 and very similar to the larger 125cc engines in other models, but completly different from the 65cc engine in the Shortster.

  • Picture 1: 1973 model
  • Pictures 2-3: 1974 model
  • Pictures 4-8: 1975 models
  • Picture 9: Speedo of 1974 to 1975 models
    • Early bikes had a speedo with a smaller diameter
  • Picture 10: Two 1974 X90s from France
  • Picture 11: Decal which was on the top of many gas tank from 1974 to 1975 models
  • Picture 12: Hangtag used in the showrooms at the dealerships
  • Picture 13: Owners manual delivered with the bike
    • contact me if you need one!
  • Picture 16: The 90cc crankcase
  • Pictures 17-19: 1975 model equipped with the optional available crash bar.
    • thats my own bike
  • Picture 20: 1975 X-90 in comparison to a Honda Dax ST-50

1973 - black, owner: Bram, Luxembourg1
1974 - black2 1974 -black3 1975 - black4
1975 - black5 1975 - black6 1975 - black7 1975 - sparkling blue8
1975 - Speedo9 owners manual10 Eagle emblem11 Handle-bar tag12
owners manual13 X90 Video, Schiranna 04 - Sven Doehler14 X90 Video, France15 Lower Engine Case16
1975 with crash-bar17 1975 X90 www.aermacchi-world.de18 X90 - Germany19 X90 vs Dax20

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Thanks to Bram from Luxembourg for the picture of his 1973 X90!
Thanks to Greg from Florida for the pictures of the black 1974 and 1975 X-90s!
Do you have further information? E-Mail: