Quadrant Motorcycles was founded by lifelong motorcyclist and engineer Johnny Cusack, built upon more than 13 years of professional OEM motorcycle engineering experience alongside many years restoring, recommissioning and preserving classic and modern machines privately.

Holding degrees in both Motorcycle Engineering and Mechanical Engineering, Johnny spent much of his professional career within motorcycle development, leading prototype build, testing and production-readiness activities across a wide range of projects.

This included more than eight years working within high-performance motorcycle development programmes, supporting the development and testing of machines competing at the highest level of road racing, the Isle of Man TT achieving top-six finishes in Senior TT and Superbike TT competition.

That engineering background shaped the philosophy behind Quadrant Motorcycles: a workshop focused not only on appearance, but on mechanical integrity, engineering correctness, attention to detail and long-term reliability.

From sympathetic recommissioning and preservation work through to full restorations and bespoke rebuilds, every project is approached with the same mindset — understand the machine properly, respect its history and deliver workmanship without shortcuts.

Quadrant Motorcycles specialises in:

• Classic motorcycle restoration

• Recommissioning long-term stored machines

• Mechanical refurbishment and fault diagnosis

• Carburettor and ignition system setup

• Chassis, suspension and brake overhaul

• Sympathetic preservation projects

• Period-correct detailing and finishing

• Bespoke engineering-led custom builds

Rather than operating as a high-volume workshop, Quadrant focuses on carefully selected projects where quality, transparency and craftsmanship take priority over speed.

Many of the motorcycles featured throughout this website represent projects completed personally by Johnny over many years, reflecting a longstanding passion for engineering, restoration and the preservation of historically significant machines.

At its core, Quadrant Motorcycles exists for owners who value honesty, precision and genuine enthusiasm for motorcycles — whether preserving a family heirloom, reviving a forgotten classic or creating something entirely individual.