In the off-road world of modern times, KTM stands loud and proud and are best known for their motocross, enduro and rally raid machines. As the European market leaders who also have Husqvarna under their arm, with the acquisition of the Gas Gas brand the Austrian marque now can add a trials model to its range. It is not their first move into the motorcycle trials market as we ‘Flashback’ here to an ambitious project that began during the ’70s and ended with the KTM 325T trials machine. Yes, a KTM trials machine was a reality... some 43 years ago!
Rewind the clock to 1975 when the big boss at the Austrian manufacturer, Erich Trukenpolz, the T in KTM, was the originator of the motorcycle trials project. The country’s trials specialist at the time was Walther Luft, who was also an excellent rider and engineer, and Erich was able to convince him to come and work in the factory at Mattighofen, Austria.
Luft had already worked with another Austrian motorcycle manufacturer, Puch, and during his time with them had produced a superb, innovative and superlight 250cc trials machine. Luft agreed to join KTM in the hope of seeing his ideas reach production as his efforts at Puch hadn’t gone beyond the doors of the research-and-development department of the rival Austrian manufacturer.
AUSTRIA ENTERS THE TRIALS EACE
The ‘big’ three in the trials world were the very successful Spanish factories of Bultaco, Montesa and Ossa, who were already in fierce competition with the Japanese in this market sector in the mid-seventies. Honda, Kawasaki, Suzuki and Yamaha had already laid their cards on the table with production machines. Notably, it was Yamaha who had already made significant inroads to the clubman market with its superb TY range of machines headed by Mick Andrews. Now, there could be another motorcycle manufacturer trying to capture a share of the market as the Austrian factory was already a big player in motocross and enduro. It was now time for KTM to enter the trials race.
In early 1975, Walther Luft had started work in earnest on the trials project with many new ideas in mind. As he had done at Puch before, he was obliged to start the basis of the project with an existing engine. He worked in close cooperation with the other KTM engineers, with Heinrich Wieditz heading the team. Luft was to develop a machine that didn’t have the ambition of being revolutionary in concept but one which was to provide a credible alternative to the hugely popular Bultaco, Sherpa and Montesa Cota models, amongst others. Along with strong global sales, they also had the competition pedigree of providing winners in the new FIM Trial World Championship, which had been upgraded from the European Championship to the full FIM title in 1975, when Martin Lampkin had won for Bultaco.
ENDURO TO TRIALS
Walther Luft selected the engine from the KTM 400GS enduro machine with an actual cylinder capacity of 355cc as the starting point for the trials engine. He chose it for its big flywheel and inherent inertia, and it was reduced in capacity to 240cc with a 70mm bore and 62mm stroke, which was the same as the enduro model. The 240cc engine size was selected to take advantage of the VAT situation in France, which at the time was a very important market factor as
“The 240cc engine size was selected to take advantage of the VAT situation in France, which at the time was a very important market factor…”
machines exceeding 240cc were heavily taxed. A heavier flywheel magneto was fitted along with a lower geared primary transmission: 20/73 for the trials project as against 25/69 of the GS enduro machine. The clutch was modified to use just four drive plates, and the six enduro ratio gears were also retained. In particular, Luft made use of the engineering exercise to reduce the cooling fins of the cylinder and head to save weight. According to KTM, the engine developed between 17 and 18bhp, and between 7,500 and 7,800rpm, which was slightly less than the Bultaco Sherpa 350 or Montesa Cota 348 models which were the reference machines of the time. The bigger engines of the Spanish opposition also had more low-down power.