Model Designation LettersX
Model Years1973-1975
Vehicle Identificiation2D
Bikes Produced1973: 8250;
1974: 7019;
1975: 1568;
Price2456 francs T.T.C (in France)
Electrical System6 Volt
Top Speed
Front suspensionTelescopic oil dampened, three different types over the year: Cerrani, Marzocchi, Betor
Rear suspensionSwinging arm, twin shocks, oil dampened;
Front wheel tire3.00 x 10 (74 & Later: Pirelli MT 74)
Rear wheel tire3.00 x 10 (74 & Later: Pirelli MT 74)
Front brakeInternal Expanding
Rear brakeInternal Expanding
Rims (Front & Rear)Disc Wheel, WM1= 1.6x 10"
Tire pressure (Front)18 PSI
Tire pressure (Rear)22 PSI
Dimensions & Weight
Overall length145 cm
Handlebar width84 cm
Ground clearance15 cm / 5.9 in.)
Wheelbase40.7 in.
Seat(s)1 Person
Saddle Height
Fuel Tank5,3 Liters / 1.4 gallons
Fuel Tank Reserve
Transmission Oil1,37 litres (1 quart)
Type2 cycle, single cylinder, air cooled
Bore48 mm (1.89 inches)
Stroke50 mm (1.97 inches)
Piston displacement90,43 ccm
Max. Torque
Gearshift pattern4 speed, 1 down - 3 up; left side
Compression ratio9.2: 1
Lubrication systemFuel and oil mixture, automatic oil pump
Starter systemPrimary kick
CarburetorDell Orto SH2/20
ClutchWet, multi plate
Gear ratios1st: 20,06, 2nd: 11,23, 3rd: 7,38, 4th 5,77
Spark Plug

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.

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

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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: webmaster@aermacchi-world.de