Aprilia STX 125 Make Model. | Aprilia STX 125 | Year | 1985 | Engine | Two stroke, single cylinder | Capacity | 124cc / 7.6 cu in | Bore x Stroke | 52.8 mm x 57mm | Compression Ratio | 14.5:1 | Cooling System | Liquid cooled | Induction | 26 Dell'Orto PHBH AS | Ignition | Electronic | Starting | Kick | Clutch | Multi-disc oil bath | Max Power | 15.7 kW / 21hp @ 8000 rpm | Transmission | 6 Speed | Final Drive | Chain | Frame | Double cradle tubular steel | Rake | 26.5° | Trail | 86 mm / 3.4 in | Front Suspension | Marzocchi ?32 mm, non-adjustable | Rear Suspension | Swingarm with single shock absorber | Front Brakes | Single ?240 mm disc | Rear Brakes | Single ?230 mm disc | Front Tyre | 100-90 -16 | Rear Tyre | 100-90 -18 | Seat Height | 800 mm / 31.5in | Dry Weight | 104 kg / 229 lbs | Top Speed | 135 km/h / 83.9 mph | | |