The magic of Marcus

Rex’s Speed Shop in Sussex is a vital source of replacement ignition, generator and ignition systems for classic Japanese machines. John Nutting talked to Marcus Rex

- JOHN NUTTING

Deterioration is a fact of life with old classic motorcycles, and more than anything it is the electrical systems that suffer the most.

The components most vulnerable are generators and ignition systems where heat and corrosion conspire overtime to undermine their performance, often in mystifying ways. Replacing parts with new old stock is fraught because even the original parts weren’t particularly good, and anyway never designed to last 50 years or more.

With this in mind, former aircraft engineer and electronics fan Marcus Rex first designed a better generator and ignition for a Yamaha four-stroke 500cc single that led to the establishment 10 years ago of Rex’s Speed Shop. Electrical systems for TZ road racers and YZ motocrossers followed, along with generators and ignitions for Suzuki twins and the demanding Kawasaki two-stroke triples.

Since then the business has expanded out of the little office on a farm in rural Sussex to a larger unit that employs a number of trained staff engaged in manufacturing a range of electronic systems for keeping old bikes on the road. “The motorcycles came first though,” Marcus told me back when we first met in 2014. His first big Yamaha was an XS650 twin, but when working at a motorcycle dealership in the early 1990s he found some literature for the SR500 which he liked, later buying three. “I just love them, and used to commute to work on them.”