The Michael ("Mick") Brough Collection, 1931/32 Sunbeam 493cc 'Model 90'

Among the finest sporting motorcycles of the pre-war era, the Sunbeam Model 90 earned an enviable reputation for quality engineering, reliability and performance. Powered by a 493cc overhead-valve single-cylinder engine, the Model 90 was developed from the marque's successful competition programme and remains highly regarded by enthusiasts of vintage British motorcycles.

This example was acquired by the late Michael Brough on 21 June 2023, having previously been registered overseas. The motorcycle was first registered in the UK on 1 October 1998 and, according to the accompanying HPI report, has had five former keepers. Prior to Mike's ownership, the machine formed part of the collection of noted Sunbeam enthusiast Les Leach of Witney, Oxfordshire.

A well-used participant in vintage motorcycling events, the Sunbeam was extensively campaigned by Mike and carries event stickers from the Classic Bike Burn Up at Castle Combe (2025), Curborough Charity Sprint, and Les Coupes Moto Légende (2025).

The registration number 'PSJ 286' is an age-related mark issued by the DVLA from a series originally allocated to the Isle of Bute, which has been used for age-related registrations since February 1997.

Prospective purchasers should note that the engine number stamping does not appear to conform fully with the factory style typically associated with Sunbeam production. The recorded engine number, N6011, is believed to relate to a 1932/33 Model 90 engine, although certain anomalies exist.

Research undertaken suggests that the 'N' prefix is generally associated with single-port cylinder head engines, whereas twin-port examples are more commonly found bearing an 'NN' prefix. While the serial sequence falls within a plausible 1932 production range, all examined and documented 1932 Model 90 examples have carried the 'NN' prefix.

It is noted, however, that a number of 1933 Model 90 engines are known to have been stamped with the 'N' prefix and carry serial numbers relatively close to this example. As a result, it is considered likely that the motorcycle has been assembled from components originating from more than one machine, as is often encountered with vintage motorcycles that have enjoyed long and active lives.

The motorcycle's early history remains uncertain. Research notes compiled by Mike suggest that the machine may have been used in the 1932 Manx Grand Prix, although no conclusive evidence has been found to substantiate this theory. The file also contains references indicating a possible association with both Formula One team principal Frank Williams and Pink Floyd drummer Nick Mason; however, no documentary proof has been located to support either connection. Nevertheless, these intriguing avenues may warrant further investigation, and prospective bidders may wish to undertake their own research into the motorcycle's history and provenance.

The machine is offered with the following:

• 1929 photocopy parts list
• 1930 Model 9 factory documentation
• 1931 catalogue models literature
• 1931 Model 90 documentation
• 2023 purchase invoice
• Potential Frank Williams & Nick Mason provenance link
• Gearbox instructions
• Collection of invoices
• Historic MOT certificates
• Two historic V5C Registration Certificates (Leach family ownership)
• Current V5C Registration Certificate

Following a period of inactivity, this motorcycle will require recommissioning and/or restoration to a greater or lesser extent before returning to the road and thus is sold strictly as viewed. Prospective purchasers should satisfy themselves with regard to this motorcycle's completeness, history, authenticity, originality and mechanical condition prior to bidding.
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