• KTM is arguably the best mid-bore enduro maker in the world.Motorcycle Exhaust image by Billy Tait from Fotolia.com
  
  Austria's KTM has gained a reputation as one of the premier off-road, adventure touring motorcycles in the world. KTM no longer makes a 600 cc machine -- they manufactured 600s in many variants from 1984 to 1993. While KTM's 600 cc motorcycles were offered for slightly different applications to accommodate differing market regulations around the world, the actual 600 cc engine saw very few changes during its production run. Even KTM's later 620 cc single-cylindered bikes and current 640s are built around the engine design of the 600.
  
  

600 cc Configuration and Performance

• The basic configuration of all KTM 600 cc engines, as seen in the original 600 Enduro Sport, was a single cylinder, overhead cam, four-stroke. With a bore of 94 mm, a stroke of 81 mm, and a compression ratio of 9:61, the original 600 made a modest 27 horsepower at 6,500 RPM. The five-speed transmission the engine powered the Enduro Sport a top speed of 80 mph, though it produced adequate torque to carry the bike much faster with a taller drive sprocket.
  
  

600 cc Engine Models

• The original KTM Enduro Sport 600, then the, XC Enduro Sports, and XC Enduro Sport Es, were followed in 1987 by the LC 4. Some variation of the LC model was manufactured until the penultimate year of the LC 4, 1992. In some markets, the LC 4 was made in a de-tuned "reduced effect" model. Other 600 cc-powered models include the 600 Rallye and Inca 600 LC 4. The final entry was simply the 1993 600 Enduro, before KTM moved on to 620 and 640 cc singles.
  
  

Variations

• While KTM has grown in popularity, it is a much smaller company than any of the major Japanese makers. KTM was not equipped to design as many variations or make as many year-to-year changes as larger companies. Their popularity and success has allowed them to increase variants, but during the time the KTM 600 was their primary power plant, KTM made very few changes to the engine. Though some 600s used four-speed transmissions and they were eventually upgraded to water-cooling, and minor changes were made to compression, the core of the 600 remained unchanged.