Quadrant Motorcycles was founded by Johnny Cusack, a motorcycle engineer who has spent most of his working life developing motorcycles — and most of his spare time taking them apart.

His career in the motorcycle industry started in 2009, and has since spanned OEM motorcycle design and development, prototype build and testing, British Superbike and the Isle of Man TT.

That experience is backed by an FdEng in Motorcycle Engineering and a BEng (Hons) in Mechanical Engineering, combining hands-on motorcycle design and development with a strong engineering foundation.

Quadrant grew out of the motorcycles that were being restored and rebuilt long before there was a business: British classics, two-strokes, race bikes, homologation specials and generally anything interesting enough to warrant saving.

Inevitably, the professional engineering approach found its way into those projects.

Measure rather than guess. Understand the problem before replacing parts. Preserve good original components where possible. And if something isn't right, find out why.

That's essentially how Quadrant works today.

Restoration Without Surprises

Classic motorcycles don't always cooperate with the plan.

An engine that looks healthy externally can tell a different story once it's apart. A fuel tank can hide decades of corrosion. Previous repairs aren't always obvious, and a motorcycle that's been standing for twenty years doesn't necessarily need everything replacing simply because it's old.

Our approach is to understand the motorcycle first, establish what actually needs doing and keep the owner involved as the picture develops.

Sometimes that means a complete restoration. Sometimes it's an engine or chassis rebuild. Sometimes the best result is simply recommissioning the motorcycle and leaving everything else alone.

The objective isn't to restore everything. It's to do the right work, properly.

Restoration. Recondition. Recommission.

Quadrant works with classic, modern-classic and interesting motorcycles where an engineering-led approach adds value.

That can mean rebuilding an engine, preserving original components, sorting a motorcycle that's been standing for years, or taking a complete project back to first principles.

We combine traditional workshop skills with the measurement, testing and development approach you'd expect from professional motorcycle engineering.

Originality matters too. Where a component can be properly cleaned, inspected and retained, we'd generally rather preserve it than replace it simply because something new is available. Equally, when a component has reached the end of its useful life, we'll say so.

The motorcycle dictates the work — not a predetermined list of parts to replace.

A Different Kind of Workshop

Quadrant isn't intended to be a high-volume motorcycle workshop.

Projects are carefully selected and undertaken with an emphasis on mechanical integrity, engineering correctness, transparency and attention to detail.

Because we're a small specialist workshop, the person you speak to about your motorcycle is also the person working on it.

Many of the motorcycles shown throughout this website started as personal projects, completed over many years before Quadrant existed. They're part of the reason the business exists today and reflect the same interest in unusual, significant and characterful motorcycles that continues to shape the work we take on.

Whether you've bought a classic and aren't quite sure what you've got, have a motorcycle that's been standing for decades, need an engine or chassis rebuilding, or have a restoration that's become bigger than expected, we'd be interested to hear about it.

No unnecessary work. No shortcuts. Clear communication about what we find along the way.

That's what we mean by:

Restoration Without Surprises.