Derbi GPR

Derbi GPR

2003 Derbi GPR
Manufacturer	Derbi
Also called	Gilera SC125 Malaguti RST 125
Parent company	Piaggio
Production	1990–2013
Class	Sport bike
Engine	50–125 cc (3.1–7.6 cu in) 1990–2009: liquid cooled, two stroke1 2010–2013: liquid cooled four stroke2
Bore / stroke	1990–2009: 56.0 mm × 50.7 mm (2.20 in × 2.00 in) 2010–2013: 58.0 mm × 47.0 mm (2.28 in × 1.85 in)
Compression ratio	12.5:1
Transmission	6-speed
Suspension	Ø40 mm upside-down fork. 110 mm. travel Rear: Monoshock. 110 mm travel, Adjustable Preload
Brakes	Front: Single 300 mm Hydraulic Disc with Four Piston Radial Caliper Rear: Single 180 mm Disc with Two-Piston Caliper
Tires	Front: 100/80-17 Rear: 130/70-17
Wheelbase	53.34 in (1,355 mm)
Dimensions	L: 79.68 in (2,024 mm) W: 28.34 in (720 mm) H: 45.66 in (1,160 mm)
Weight	225 lb (102 kg) (dry) 285 lb (129 kg) (wet)
Fuel capacity	3.4 US gallons (13 L; 2.8 imp gal)
Oil capacity	1.5 litres (1.6 US qt)

The Derbi GPR is a street motorcycle sold by Derbi from 1990 until 2013.²

The original GPR was powered by a single-cylinder two-stroke engine with a steel lined cast iron cylinder manufactured by Yamaha, but was superseded in 2010 by an all-new DOHC four-stroke four-valve model.³ It was also sold in a naked variant called Derbi GPR Naked.

The engine in the original two-stroke model is sourced from Yamaha. This engine was used in the Yamaha DTR125 Dual Sport and TZR125 sport bike. Engine parts from these two bikes will directly swap with the Derbi. It uses the Yamaha Power Valve System, a two-stroke power valve system, which consists of a rotary valve located in the exhaust port which changes the exhaust port timing and area. The power valve is controlled by an ECU and servo motor.

In 2010 the engine was changed to a new four-stroke engine.³ The single cylinder engine features double overhead camshafts and four valves.⁴