LOT 243

The David Plant Collection 1921 Norton 633 Big Four Registration no. EY 1265 Frame no. 3084 Engine no. 20681 (see text)

Sold for £7,475 inc. premiumLot to be sold without reserve

Lot 243

The David Plant Collection, 1921 Norton 633 Big Four

The Spring Stafford Sale - The International Classic MotorCycle Show|26 April 2026, 11:30 BST|Stafford, Staffordshire County Showground

The David Plant Collection
1921 Norton 633 Big Four
Registration no. EY 1265
Frame no. 3084
Engine no. 20681 (see text)

Norton relied on proprietary engines in its formative years - winning the inaugural Isle of Man TT with a Peugeot-engined machine - before introducing its own design of power unit in 1907. The long-stroke (82x120mm) sidevalve single displaced 633cc and the new model it powered became known as the 'Big 4'. Smaller capacity versions followed and in 1911 the 500 adopted the classic 79x100mm bore/stroke dimensions which would characterise the half-litre (actually 490cc) Norton for the next 50 years. Norton's sidevalve engines were revised for 1914 and in 1921 the Model 16, as it had become known, received a new lower frame, becoming the 16H. Considered by many to be an ideal sidecar 'tug', the Big Four (and 16H) would be continuously up-dated for the next 30-plus years, many seeing service with Allied forces in WW2. Post-war, the Big Four was revised with a shorter (113mm) stroke for a capacity of 597cc before taking its final bow, alongside the16H, in 1954.

This Big Four is an older restoration that has belonged to our vendor since 1983. It should be noted that the gearbox is stuck and we have been unable to test for compression. Offered with old/current V5/V5C documents. It should be noted the accompanying documents list the engine number as 20661 opposed to 20681 (a typographical error).

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.
Key not required

Footnotes

All lots are sold 'as is/where is' and Bidders must satisfy themselves as to the provenance, condition, age, completeness and originality prior to bidding.

Please see the Auction Information and Guide for Buyers at the top of the main sale page, for bidders' obligations. The Spring Stafford Sale

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This Lot will be auctioned on Sunday 26 April, with the auction starting at 11:30am BST.

Saleroom notices

Please note the engine appears to be seized.

Additional information

This auction is now finished. If you are interested in consigning in future auctions, please contact the specialist department. If you have queries about lots purchased in this auction, please contact client services.
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The David Plant Collection, 1921 Norton 633 Big Four

The David Plant Collection1921 Norton 633 Big FourRegistration no. EY 1265Frame no. 3084Engine no. 20681 (see text)

Footnotes

Saleroom notices

Additional information

Auction information

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The David Plant Collection
1921 Norton 633 Big Four
Registration no. EY 1265
Frame no. 3084
Engine no. 20681 (see text)