• Year of manufacture 
  • Motorcycle type 
  • Engine number 
  • Lot number 
  • Condition 
  • Colour  
  • Location


1953 Ariel 998cc Square Four Mark I
Registration no. NVU 939
Frame no. ES4745
Engine no. RD1025

Totally redesigned, the Ariel 'Square Four' re-emerged in 1937 as the 995cc Model 4G. An exercise in weight shedding saw the engine's cast-iron top end replaced by alloy components for 1949, this revised model being known as the 'Mark I'. To date, the innovative Ariel Square Four remains unique in motorcycling history; a true 'gentleman's motorcycle', this refined yet charismatic machine retains an enthusiastic and loyal following, and is highly prized by discerning enthusiasts.

This Mark I was purchased in 1970, ridden regularly until 1980 and then stored until 2003 when it was rebuilt. A spare 1951 Mark I engine ('RD1025') was fitted during the rebuild while the original ('XJ697') was away being overhauled. The original engine, now reconditioned, is included in the sale together with the original Solex carburettor (an Amal Concentric is fitted at present). The machine also comes with a quantity of spares to include a gearbox, chain cases, and clutch parts. Routinely maintained and MoT'd since the rebuild's completion, the machine is described by the vendor as in generally good condition, the only notified fault being a noisy 3rd gear. Accompanying paperwork consists of an old-style continuation logbook, Ariel Owners MCC dating letter, and old/current V5/V5C registration documents. It should be noted that the latter incorrectly records the frame number as 'E5745', a not uncommon typographical error.

Bonhams 1793
101 New Bond Street
United Kingdom
Contact Person Kontaktperson
First name 
Bonhams Collectors’ Car department