These are the known mechanical and performance specifications for your 2004 Gilera TT Surfer 50.
Basic Specs

Engine
Displacement49.90 ccm (3.04 cubic inches)
Type
DetailsSingle cylinder, two-stroke
Max RPM
Compression
Bore/Stroke
Valves/Cylinder
FuelingCarburettor. Dell´Ortho 12-14 mm
IgnitionKick
Exhaust
Lubrication
CoolingLiquid
Fuel Economy & Polution
Fuel Consumption
Fuel Capacity5.00 litres (1.32 gallons)
Emissions
Chassis
Frame Type
Rake
Trail
Front SuspensionNon-inverted forks
Front Travel
Rear Suspension
Rear Travel
Seat
Seat Height
Alt. Seat Height
Total Height
Total Length
Total Width
Ground Clearance
Wheelbase
Dry Weight72.0 kg (158.7 pounds)
Wet Weight
Wheels & Brakes
Front Tire/Tyre
Rear Tire/Tyre
Front BrakesSingle disc. 2-piston calipers
Front Brake Diameter
Rear BrakesExpanding brake (drum brake)
Rear Brake Diameter
Wheels
Comments
It´s the ´cheap version´ of the Gilera H@K