KTM’s 640 LC4 engine is one of my favorites of all time. Although it vibrates like a paint shaker on meth and can be prone to some tedious maintenance, it’s a compact and diverse little power plant. The versatile Austrian single found its way into a variety of KTMs including the company’s enduros, supermotos, and adventure bikes. It also served in the Duke II, one of KTM’s most intriguing scoots.
Following KTM’s even lesser known 620 Duke, the Duke II was introduced in 1999 and produced until 2005. It sort of loitered on the line somewhere between standard streetbike and full blown supermotard. I believe its official designation was “streetmoto.” But, at a time when most motards were the products of tinkering with putting sticky, street-oriented tires on a dirtbike in mid-winter basements in Michigan, the Duke II was a few years ahead of the curve, as the bigger companies—Suzuki, Yamaha, Honda, etc.—would only begin to produce factory motards in the mid-2000s.
Like these later, more aggressive motards, the Duke II was intended primarily as a city bike and brief backroads bomber. Anyone who has straddled an LC4 engine on a stock KTM seat knows that brief rides are about all that can be comfortably managed. With a three gallon gas tank and an average of 45 miles per gallon, the Duke II demands relatively frequent stops, much to the delight of its rider’s hind end.
My most notable experience on an LC4 was when my Honda CB-1 broke down in Atlanta, forcing me to borrow a friend’s 640 Adventure — the taller, more enduro-oriented cousin of the Duke II — to get back home to Florida. I wasn’t even out of the Atlanta metro before I could no longer feel my hands. Somewhere around Macon, my feet and butt joined the numbness party, and, 350 miles later, as I parked the fine Austrian steed in my Florida garage, I could no longer feel any part of my body. Not a single, solitary cell. It was clear that this motor, though full of torque and smiles, was intended for shorter bursts.
Yet, Craig’s better half, Lisa, rode her Duke II over 600—six hundred twenty eight point six five—miles from Vermont to an Adventure Rider rally in West Virginia.
That’s six hundred LC4 miles on a bike that is smaller, lighter, and more susceptible to the motor’s brain scrambling ways than the Adventure. And, she did it in a single shot. It was Lisa and the Duke II, and that was it. No fancy accoutrements or accessories. The bulk percentage of the rally’s other attendees arrived on farkled up BMWs and Triumphs and Japanese sport tourers. By comparison, they were all a bunch of prim and pampered pansies, shown up by a jam-making, chicken-tending lawyer on a thumper. To date, that single ride on a Duke II is one of the most impressive, completely badass feats I have ever witnessed.
Alas, after a little under a decade, the 640 LC4 engine was upgraded to the current 690 engine, which boasts gains in both torque and horsepower. The Duke II departed with the 640 engine, replaced by the 690 Duke and leaving the motard designation behind as the new model took on a beefier, more streetbike-esque persona. The Duke II was, in some ways, an odd little motorcycle, but it was also on the leading edge of the motard craze of the 2000s and deserving of the “streetmoto” category that was truly all its own.