In building a special such as this AJS for Gordon Jackson to win his last SSDT, it is likely AMC realised they had little option but do it, as the competition world was changing. All factories in the UK industry had held firm to the belief their works teams should be seen to be riding what was in the showroom, or at least something close to it. Unfortunately for AMC what was in the showroom was becoming outdated, the trials world was realising it wanted lighter machines which meant two-strokes as, without access to a factory, carving weight off one of the traditional big bikes was beyond the ability of most enthusiasts.
Unfettered by the need to be seen riding what his employers sold, one of Gordon’s main rivals was creating a legend from a big bike and make no mistake AMC’s management knew it. Without the vast resources of BSA to help, AMC were unable to fling money at a bike but still wanted to provide the best machine they could. Despite their lack of resources the company had other attributes including Wally Wyatt, and speaking with Gordon Jackson recently he was keen to highlight the work Wyatt had put into this machine. The two men who would sanction this build – Hugh Viney and Jock West – were well aware of the way the trials scene was heading and equally aware of the resources available to them so, titanium was out but creating special parts from what they did have was more than possible.
A lightweight frame from Reynolds famous tube was fabricated to suit Gordon’s style, there was a little more ground clearance and a slightly lower seat height built into the dimensions. Aluminium engine plates reduced weight too and repositioned the engine slightly further back. Lowering the sub frame allowed shorter, lighter rear dampers to be used and building wheels around the ex-WD machine hubs by using alloy rims and brake plates also reduced the pounds considerably.
Jackson did prefer the higher performance of a short stroke engine and with a shorter stroke comes the weight saving of a shorter con-rod and barrel, not huge savings admittedly but they do add up. While it would have been nice to cast lots of bits from magnesium alloy there was a strength consideration to look at, however the rocker box covers were deemed non-stressed so they too were in lighter than standard magnesium.
A shorter, high level exhaust pipe ending in an alloy box silencer was probably a third of the weight of a standard system and fabricating a tiny oil tank from alloy sheet and slipping it between the rear engine plates not only saved the weight of the steel item but also meant shorter, lighter oil lines could be made.
Finally the sprung saddle was replaced by a foam seat pad and the resultant machine was ready for Scotland and its date with destiny. Comp shop engineer Wally Wyatt ‘knew’ Gordon had won the Scottish before the start of the trial, simply by how excited he was as he showed his bike off to everyone.
See the bike
Gordon’s ‘One Dab’ AJS forms part of the trials collection in Sammy Miller’s museum in New Milton, Hampshire.
There is an excellent website www.sammymiller.co.uk with opening times detailed.
The museum address is Sammy Miller Museum, Bashley Cross Roads, New Milton, Hampshire, BH25 5SZ
Telephone 01425 620777