These are the known mechanical and performance specifications for your 1990 Malaguti RST 50.
Basic Specs

Engine
Displacement50.00 ccm (3.05 cubic inches)
Type
DetailsSingle cylinder, two-stroke
Max RPM9500
Compression
Bore/Stroke
Valves/Cylinder
FuelingCarburettor. Dell Ortho
IgnitionCDI
ExhaustDouble under seat steel exhaust
Lubrication2 stroke
CoolingLiquid
Fuel Economy & Polution
Fuel Consumption
Fuel Capacity13.00 litres (3.43 gallons)
Emissions
Chassis
Frame Type
Rake
Trail
Front Suspension
Front Travel
Rear Suspension
Rear Travel
Seat
Seat Height
Alt. Seat Height
Total Height
Total Length
Total Width
Ground Clearance
Wheelbase
Dry Weight
Wet Weight
Wheels & Brakes
Front Tire/Tyre
Rear Tire/Tyre120/80-16
Front BrakesSingle disc
Front Brake Diameter
Rear BrakesSingle disc
Rear Brake Diameter
Wheels
Comments
Also sold in Spain as a Rieju RST 80