This is bike number 708
Sold in October of 2014 at bonhams for $13,682
http://www.bonhams.com/auctions/21898/lot/256/Text from listing
As displayed at The Bike Shed
1978 Seeley-Honda 750cc F1 Sport
Registration no. WGY 810S
Frame no. SH7-708F
Engine no. CB750E-2562558
British sidecar champion Colin Seeley bought Associated Motor Cycles' racing department when the company went into receivership in 1966. Believing that the AMC engines possessed further potential if equipped with state-of-the-art cycle parts, the previous year he had constructed the first Seeley racing frame to house a Matchless G50 engine, and the AMC purchase enabled him to produce complete Seeley G50 and 7R machines. With their improved frames, the four-stroke singles enjoyed renewed competitiveness, Derek Minter winning first time out at the start of the 1966 season on both the 350cc 7R and 500cc G50-engined Seeleys. The Seeley frame progressed from the duplex cradle MkI to the similar but lighter MkII. Down-tubes were abandoned with the MkIII, the head-stock and swinging arm pivot of which were linked solely by tubes running diagonally above the engine. The MkIV introduced towards the end of 1970 featured a revised tubing layout and continued in production until 1973, achieving further successes. Seeley's designs clearly had the potential to accommodate other, more-powerful types of engine, and commissions for frames for multi-cylinder power units soon followed, one of the first being the Seeley-Honda. Connections with Honda UK resulted in the Seeley-Honda's creation in the mid-1970s, a period when the power produced by large Japanese multis was not matched by their frames' ability to cope. Lightweight and rigid, the nickel-plated Seeley chassis was a vast improvement on the Honda version in both looks and practicality, enabling in-frame removal of the cylinder head, unlike the original. The fact that it handled better too goes without saying.
This Seeley-Honda was acquired by the current vendor in July 2013 having spent some 20 years in storage. The machine was then re-commissioned and fully serviced, receiving a new wiring loom, brakes and tyres, and on 6th July 2015 won the 'Best Multi-cylinder' award at the Brooklands 'Ace Café Ton-Up Day'. 'WGY 810S' also featured at the 'Bike Shed III' event in May 2014 and was pictured with Colin Seeley in 'Classic Bike Guide' magazine. Colin Seeley's letter of authentication is in the accompanying history file together with sundry bills, current MoT certificate and V5C document.