This Comet Special uses one of three frames built by Spondon and a Comet engine built originally by Ian Hamilton with a 90x100mm bore x stroke displacing 636cc. Note the Norton gearbox. (Courtesy of Jim Evans)

Ten Years ago, I was just starting my research to unravel the Egli-Vincent story and multiple subsequent derivates, which eventually led me to the publication of my book in 2016. Breaking this new ground, my objective was to be as exhaustive as possible. However, it became evident that identifying all specials and one offs over 50 years will be a great challenge, and thus I would certainly omit some Vincent specialists whose career or charisma had deserved to be included. So, in the months following the publications, I continued to receive valuable information, and this is how I met Jim Evans who helped me to prepare some content concerning Ian Hamilton whose life tragically ended on his 1971 Egli at Cadwell on April 4, 1999. Should a second edition of my book be published one day, this omission will be rectified among multiple other additions.

Jim contacted me a few days ago to inform me that a Comet Special using an engine built by Ian was on the market for sale, and here is its story. This project was initially started by Glenn Cuthbertson who was one of Ian’s very close and supportive friends. “Glenn was always available as a sounding board when developments were being discussed which were relevant to his skills and experience”, says Jim. “Glenn always preferred motorcycles were big singles—mainly Velocettes—building multiple bikes such a heavily modified short stroke Veloce, using a Yamaha SZR660 chassis. This Comet special is in fact the last piece of Glenn’s work, he died too soon before completing the project to build a Comet-engined road bike, using modern cycle parts based on BOTT/ BEARS racer.

Engine is fully rebuilt with a short Carillo rod, 90mm JE Squish band piston with about 8:1 CR as it meant to be a road motor, 100mm stroke in an alloy Aptec ceramic coated cylinder. Head is mildly gas flowed with a new Amal Mk2 carburator. It has a Bob Newby belt primary drive and clutch, a rebuilt Norton gearbox, a 12v generator, but no lighting kit it fitted. It also has a new BTH electronic magneto and a bespoke alloy tank by John Williams known as The Tankman.  

“This 90×100 Comet engine was originally built for Glenn by Ian, and unlike engines that Ian or I built, it is a stroked configuration which was never used in any of our race or road engines as we were trying to increase the power output by improving the combustion efficiency, using our design of squish band pistons made by JE while also increasing the power at higher RPMs with modified camshafts, high compression ratios and pistons up to 94 mm.”

This is one of 3 frames built by Spondon according to Glenn’s design. The forks, wheels, brakes, and swing arm are originally from Honda with Glenn’s alloy bridging components bracing the frame and abutting the shock/spring unit. The fitted dual seat unit is from a Yamaha Fazer as Glenn wanted the bike to useable for a pillion passenger but easily reconfigured if a new owner prefers a more sporting look, the clip-on bars are easy to alter and adjust.

“The plan, now completed, was to manufacture a new main frame which would accept all the cycle parts and running gear from a specific single donor machine, in this case a Honda CBR400RR; for this bike though, Glenn did not use a donor but sourced mainly new parts from a main dealer, and since the build has taken too long. Martin, in the interest of safety, has fitted another set of new tires.

The bike can be seen near Skipton in the UK, If you are interested, please drop me an email and I will forward it to Jim.

Philippe Guyony

The project was to deliver a modern Comet road bike, using modern cycle parts based on BOTT/ BEARS racer, hence Honda CBR400RR cycle parts.  (Courtesy of Jim Evans)

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