Sunday, 15 April 2018

The Coultas Velocette – Part 2

The following blog relates to the second of Alan’s race bikes, built in the early 70s.

Following the premature demise of Big Al’s first ‘Coultas Special’, he was on the lookout for a more suitable frame with which he could build a racing Velocette 500. In 1972 he purchased the chassis of the Myers Manx, the second frame built by Bert Myers and raced by his son Tony. The rolling chassis consisted of the MK2 frame, Norton forks fitted with a Yamaha TD1C front brake and a 7R brake at the rear.

MK2 Myers framed Coultas Special

TD1C front and 7R rear brakes

The much modified engine from his first ‘special’ was considerably off-set in the frame to mate with a Norton AMC gearbox and clutch. Other than this engine, Alan used no futher Velocette components. Stood on 18” rims, the bike looked very low and mean, to the uninitiated a Seeley MK3 lookalike. Many different make of front brake were tested over the years, but they never seemed to meet with the universal approval of riders. Some liked discs and others were happier with drums, at one period a 7R front wheel was also fitted.

Alan Coultas, Alec Swallow and Wally Dawson

The bike was now very competitive in 500cc clubman’s races and many good results followed. Sadly as with his previous ‘special’, cracks started to appear in the main frame tubes over time. As he was happy with the overall performance of the bike, Alan bought the MK3 Myers Yamaha frame. This was again modified to fit a 500cc Velocette engine, two cross-tubes being fitted to the rear of the engine and gearbox. He also purchased the Campagnolo front and rear discs brakes that were used on the Myers Manx. This consisted of a twin disc arrangement on the front and single on the rear, both being mechanically operated by cable.

MK3 Myers framed Coultas Special

The bike was small enough to support a Yamaha fairing and was altogether a very good looking and purposeful machine.

Big Al looking suitably pleased

A five speed Quaife gearbox was now fitted and gave a useful improvement in race performance. Over time the Campagnolo brake operating mechanisms were replaced with Lockheed hydraulic calipers and eventually the discs were also replaced with cast-iron items. The original Campagnolo hubs were retained.
Alan also made his own drive-side crankcase halves. As you would expect from a joiner, the patterns were made of wood and included a larger main-bearing boss and stiffeners to the crankcase mouth. They also included the required off-set to allow for the AMC chain-line used.

The crankcase half was machined to house two main-bearings, in order that the extended main-shaft was properly supported. An over-sized 1 ¼” main-shaft was fitted the drive-side flywheel and larger roller bearings used. The engine shock absorber was no longer necessary as the AMC clutch incorporated a cush drive.

Partially machined crankcase

As the bike was further developed it became increasingly competitive, even at National level. A queue of riders willing to put their leg across included:- John Beney, Trevor Beharrell, Bill Clark, Wally Dawson, Tony Myers, Dave Saville and Alec Swallow.

Bill Clark and Coultas Special

Some more links related to Alan's racing bikes:
The Coultas Velocette - Part 1

Coultas 4 valve racing Velocettes

Coultas Velo in winning action

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