1982 - 1984 Aprilia ST 125

Make Model	Aprilia ST 125
Year	1982 - 84
Engine	Two stroke, single cylinder
Capacity	124 cc / 7.6 cu in
Bore x Stroke	52.8 mm x 57mm
Compression Ratio	14.5:1
Cooling System	Liquid cooled
Induction	Ø28 mm Dell'Orto PHBH AS
Ignition	Electronic
Battery	12V 5.5 Ah
Generator	130W
Starting	Kick
Clutch	Multi-disc oil bath
Max Power	13.8 Nm / 18.5 hp @ 8250 rpm
Transmission	6 Speed
Final Drive	Chain
Frame	Double cradle tubular steel
Front Suspension	Marzocchi Ø32mm fork. non-adjustable
Rear Suspension	Swingarm with single shock absorber
Front Brakes	Single Ø230 mm disc
Rear Brakes	Ø160mm drum
Front Wheel	2.75-18
Rear Wheel	3.00-18
Seat Height	800 mm / 31.5 in
Dry Weight	104 kg / 229 lbs
Top Speed	126.8 km/h / 78.8 mph

Overview

The first road Aprilia chassis is a conventional double-cradle tubular closed with substantial reinforcements behind the headstock. If the 32mm Marzocchi fork is rather conventional, the same can not be said for the rear swingarm suspension with single shock absorber called progressive Sebach APS (Aprilia Progressive System). The system, first case among 125 Italian road, was born from the experience of Venetian house and it was certainly a novelty for the sixteen year olds. The brakes use the proven solution front disc / rear drum. The front brake system is a stndard production Grimeca.

Engine

The motor produced by Japan's Hiro (partner Aprilia mid 70s) is a direct evolution of the excellent motor manufactured for off-road models, but extensively reworked for this new role and six gear setup.

Aprilia ST125