These are the known mechanical and performance specifications for your 2010 GAS GAS Halley 125 2T.
Basic Specs

Engine
Displacement124.00 ccm (7.57 cubic inches)
Type
DetailsSingle cylinder, two-stroke
Max RPM
Compression
Bore/Stroke54.0 x 54.5 mm (2.1 x 2.1 inches)
Valves/Cylinder
FuelingCarburettor. 26 mm
Ignition
Exhaust
Lubrication
CoolingLiquid
Drivetrain
Gearbox6-speed
Final DriveChain
ClutchMultiple disks in oil bath, hydraulic
Driveline
Fuel Economy & Polution
Fuel Consumption
Fuel Capacity7.40 litres (1.96 gallons)
Emissions
Chassis
Frame TypeDeltabox*, made with Cromoly tubing. Aluminium swing arm.
Rake
Trail
Front SuspensionFork, 41 mm.
Front Travel255 mm (10.0 inches)
Rear SuspensionOne-piece aluminium swing arm
Rear Travel246 mm (9.7 inches)
Seat
Seat Height945 mm (37.2 inches) If adjustable, lowest setting.
Alt. Seat Height
Total Height
Total Length
Total Width
Ground Clearance
Wheelbase1,460 mm (57.5 inches)
Dry Weight99.0 kg (218.3 pounds)
Wet Weight107.0 kg (235.9 pounds)
Wheels & Brakes
Front Tire/Tyre80/90-21
Rear Tire/Tyre110/80-18
Front BrakesSingle disc. Twin piston caliper.
Front Brake Diameter260 mm (10.2 inches)
Rear BrakesSingle disc. Single-piston
Rear Brake Diameter220 mm (8.7 inches)
Wheels
Comments
Spanish made bike.