Classic Dirtbike

A glance at…

Trials they were a-changing… so AMC sanctioned something special for Gordon Jackson’s 1961 works machine. Words: Tim Britton Pics Joe Dick at Mortons Archive

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… Jackson's Ajay in the Miller Museum.

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 Unfortunat­ely for AMC what was in the showroom was becoming outdated, the trials world was realising it wanted lighter machines which meant two-strokes as, without access to a factory, carving weight off one of the traditiona­l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

❝ Gordon Jackson praised Wally Wyatt's work.❞

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.

 ??  ?? Above: AMC could have sold hundreds of replicas but could the club rider actually use them as Gordon Jackson did? Sadly most wouldn't, as even Jackson's contempora­ries deemed it unrideable.
Above: AMC could have sold hundreds of replicas but could the club rider actually use them as Gordon Jackson did? Sadly most wouldn't, as even Jackson's contempora­ries deemed it unrideable.
 ??  ?? Left: Gordon's 1961 SSDT riding number sits above what must be one of the two most famous motorcycle registrati­ons in trials history.
Left: Gordon's 1961 SSDT riding number sits above what must be one of the two most famous motorcycle registrati­ons in trials history.
 ??  ?? Right: AMC rarely fitted an air filter to their bikes, instead relied on a waterproof cover to prevent the scenery entering the carburetto­r.
Right: AMC rarely fitted an air filter to their bikes, instead relied on a waterproof cover to prevent the scenery entering the carburetto­r.
 ??  ?? Above: Ace comp bike builder Wally Wyatt really went to town on what would become Jackson's last works AJS, and the bike bristles with special features.
Above: Ace comp bike builder Wally Wyatt really went to town on what would become Jackson's last works AJS, and the bike bristles with special features.
 ??  ?? Right: A small, singleside­d front hub with aluminium brake plate saved lots of weight on the front end and a Tommy bar welded to the spindle meant a spanner wasn't needed.
Right: A small, singleside­d front hub with aluminium brake plate saved lots of weight on the front end and a Tommy bar welded to the spindle meant a spanner wasn't needed.
 ??  ?? Below: Lighter, lower, higher and shorter… a special machine built for one person to use and not entirely suitable for anyone else to ride.
Below: Lighter, lower, higher and shorter… a special machine built for one person to use and not entirely suitable for anyone else to ride.

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