Yamaha Ascot Scrambler - CLASSICS REMEMBERED

In the late 1950s California was a hotbed of every kind of motor racing because (1) the aircraft industry was prospering, pumping money into a million households and (2) engineers, machinists, and fabricators were all having fun building things from the cast-off materials and surplus of that industry.

Japan's motorcycle industry had saturated that country's market and was beginning to export to the US. Karting came into being, putting thousands of two-stroke engines into the hands of innovative builders like the young Erv Kanemoto. My very first knowledge of Yamaha's existence came to me in a karting magazine containing photos of a special built by McCulloch technician Jim Yamane, powered by one of Yamaha's early production vertically-split twins. Yamaha's YDS-2 of 1963-4 could, in the right hands, smoke off the British twins and Sportsters that then ruled the streets.

At Ascot Park, an intensive “technical university” had been operating for years as engine builders taught themselves how to improve airflow and pioneering rider-engineers such as Albert Gunter and his acolyte Dick Mann quietly showed competitors the value of rear suspension on this half-mile dirt-track. Competition was close among a large group of active riders – ideal conditions for fast talent development.

Drag racing was another area of hot activity. Today the aftermarket allows us to shop for almost everything needed by keyboard, but in 1960 you had to have ideas, have skills, and have the time in which to develop working hardware that could win races.

In all these forms of racing, ideas were far more valuable than ‘checkbook penmanship’. It was an exciting time.

Yamaha management had decided at the end of the 1950s to pursue two areas in racing – the European road race Grands Prix, and AMA racing in the US. Two competition departments resulted, one designing from scratch and the other basing its work on existing production models. A special branch of that history tells the tale of the Catalina bikes, the “Yellow-Tankers”, early TD1s, and then the over-the-counter TD1-A on which Don Vesco set a Daytona record.

What was more natural, therefore, than to combine the horsepower of this fast-improving line with an off-road chassis so that the Yamaha name could be seen by thousands more enthusiasts? The result was the Ascot Scrambler, so easily transformed into a dirt-tracker.

In retrospect, the power of those twins was really too explosive for many conditions, so the real era of two-stroke dirt-track success began with the super-light Spanish Bultacos and OSSAs, followed by Yamaha's DT series and Honda Elsinores.

But there were the elements, available at any Yamaha dealer. You didn’t have to be an established Ascot “wizard of tune” to have a go. Yes, as you jetted down and the evening intensified the lean-out process by becoming cooler, you could seize. Big deal! A fresh piston and ring were six bucks. Hydrochloric acid plus some rubbing and the aluminum was gone from your cylinder. A pass with the hone, ten minutes of assembly and – DING! - you were running again. This was racing for everyman, and the necessary skills and knowledge flowed freely among karting, drag racing, motorcycle dirt track, outboards, and road race.

For kart racer Erv Kanemoto, making extra transfer ports was routine. Drill a pair of holes into the cylinder where ports needed to be. Drill a matching pair in an open area in the crankcase. Join them in pairs with flexible Tygon tubing, then cover with fast-curing Marine-Tex filled epoxy. When the epoxy set, pull out the Tygon and there were your ports. Top racers took literally dozens of such modified engines to karting nationals.

Shown an Ascot-like Yamaha TD1-B cylinder by a drag racer, Kanemoto must have been impressed by the potential; like the Ascot Scrambler, its cylinders had only two dinky transfer ports each, leaving acres of bare, undeveloped cylinder wall. When he cut pairs of gulley ports served through holes in the pistons, the bike went faster. Word got around. Soon he was “summoned” to supply such a set to Yamaha International. The TD1-C of 1967 came with the gulley ports, and the TD2 of 1969 had four real-deal transfer ports, all fed from the crankcase. Game on.

This is how hot-rodding works. Detroit for years scorned hot-rodding as warranty-voiding “tinkering”, but when winning NASCAR races began to boost sales, experienced men like the late Smoky Yunick were summoned to corporate HQs and listened-to with something like respect (“Look, guys, don’t spook these people. Just keep your traps shut and listen.”). Corporate engineers were aces at cost control but knew jack about racing, so this was their quickest path to understanding. Years later, it would be the late Don Tilley, summoned to Milwaukee to tell the degreed engineers how to keep their 883 Sportster racers from smoking on closed throttle. Engineering is understanding, not textbooks.

The easy availability of affordable raw material like the Ascot Scrambler was food for the imaginations of creative builders all over the US. Soon the whine of Foredom and Dumore flexible-shaft grinders could be heard throughout the land as these builders constantly advanced the state of the art.