1992 Aprilia AF1 Sport Pro

Restore • Recondition • Recommission

This 1992 Aprilia AF1 Sport Pro arrived at Quadrant Motorcycles with a story familiar to many enthusiasts of the pre-internet era.

The owner purchased the motorcycle in 1999 at just 15 years old — drawn to the sharp styling, race-inspired engineering and unmistakable character of the Italian two-stroke sports bike. At the time, sourcing parts and technical information for specialist motorcycles like the AF1 Sport Pro was exceptionally difficult, particularly before online forums and global parts marketplaces existed.

Despite best efforts, the motorcycle only briefly ran before being pushed into storage as life moved on. The owner left home, and for decades the Aprilia remained untouched beneath a blanket in his parents’ shed.

When the project finally returned to Quadrant Motorcycles, the motorcycle was in an extremely poor mechanical state. The engine had been left partially exposed to the elements, allowing significant moisture ingress and severe internal corrosion throughout the crankcases and rotating assemblies.

However, despite its condition, one particularly important component remained intact — the original Gilardoni cylinder barrel.

Recognising the importance of preserving the motorcycle’s originality and character, the decision was made not to use an aftermarket alternative or compromise rebuild. Instead, a genuine NOS Gilardoni barrel was sourced as the foundation for a full engine restoration and sympathetic performance rebuild.

Work completed to date includes:

• Complete Rotax engine teardown and restoration

• Genuine NOS Gilardoni cylinder barrel sourced and installed

• New piston and ring assembly matched to NOS cylinder

• New crankshaft assembly due to severe corrosion damage on original

• New connecting rod, big-end and little-end bearings

• New main bearings throughout

• New gearbox bearings including rare NOS components

• New clutch bearings and clutch pack

• New balancer shaft bearings

• Full gasket and seal replacement throughout

• New Italjet cylinder head fitted

• Cylinder squish clearance measured and set to a softer road specification for improved reliability and reduced detonation risk

• Gearbox, selector forks and selector drum assemblies stripped, refinished and rebuilt

• Balancer and primary drive gears refinished

• New VForce 3 carbon reed valve system installed

• Dell’orto VHSB 34mm carb, stripped, vapour blasted and fully rebuilt with genuine parts.

• Oil injection pump stripped, rebuilt and recommissioned

• Starter bendix assembly replaced due to corrosion damage

• Plastic balancer, oil pump, kickstart and gearbox drive gears replaced

• Shift mechanism shaft sourced and replaced after previous owner modification damage

• Electronic power valve system converted to pneumatic operation at customer request for improved tunability and road usability

• Crankcases and engine covers vapour blasted and retained in raw aluminium finish to preserve the factory racer aesthetic

Given the highly tuned nature of these early Italian two-stroke performance engines, careful attention was paid throughout the build to reliability, rideability and long-term road use rather than outright peak performance.

Alongside the engine restoration, initial chassis restoration and refurbishment work has also been completed, with the wider chassis specification and final build direction currently being developed in collaboration with the customer before the next phase of the project begins.

This AF1 Sport Pro represents more than simply a motorcycle restoration — it is the revival of a teenage dream machine left waiting quietly for over two decades.

Quadrant Motorcycles specialises in classic motorcycle restoration, two-stroke engine rebuilding and vintage motorcycle recommissioning from our workshop in Donington, East Midlands, UK.