1997 ATK 605 DSES
Dual Sport Electric Start

A Works Bike For the Regular Guy
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Imagine getting to design and build your own dirtbike—like Jesse James (of West Coast Choppers) or Orange County Choppers do for custom street bikes—except a dirt bike. Imagine being able to build a motorcycle to satisfy all your nearly forgotten fantasies of owning a hand-built, factory works bike. Now imagine throwing all those conceptions away. Imagine a bike made with the best of everything—a bike so complete that about all you can really do to it is ride it. That motorcycle exists and sadly, most people have never even heard of the company: ATK.

 Modern dirtbikes are really good but lets face it, design compromises have to be made or they'd cost twice what they do. In the interest of reducing costs, cast hubs are used instead of billet. Less expensive (and lower performing) suspension components are chosen. Weak rims are laced with cheap spokes and shod with lackluster tires. When you are going to sell 20,000 motorcycles, lower quality chains, handlebars, controls, cables, air filters and every other component manage to find their way onto the bike. To most people, dirt bikes get replaced every few years so why build them to last more than a season or two? This is why there is such a healthy aftermarket for motorcycles. For the person who constantly breaks parts or needs that performance, somebody has to fill the void.


ATK was founded during the late 1970's search for the 'next big thing' in suspension technology. At the time, every strange contraption that could be dreamed up was being tried in the off road market. Aimed at the same market as the Preston Petty "No Dive", Horst Leitner invented a product called the A-Track. Basically, it was a dual sprocket idler assembly that attached to the swingarm pivot of various bikes. It forced the upper and lower runs of the chain to run parallel. The logic is that if the chain ran parallel to the swingarm there would be no power-on squat of the rear suspension. It was a good idea, though its benefits became marginal as suspension technology improved. Horst called his new company ATK which was a consonant-contraction of 'A-Track'.

 Horst went on to design and build another product to move the rear brake disk to the countershaft sprocket. Strange yes but it accomplished two things: it reduced unsprung weight on the rear wheel and reduced the brake plumbing so pedal feel was much firmer. The problem was that with the 3:1 reduction ratio between the sprockets, the transmission mounted brake proved a tad vague in feedback. It also had a very small swept area and limited air flow around the engine so brake fade became a factor. Nonetheless, ATK was a company founded on innovative designs. During the same time period, there was a growing contingent of people wanting to race four stroke motocross bikes. Ironically, Rotax built an engine but their Can Am Sonic and the KTM 504 were the only ones using it at the time. It was a free-market engine so Horst began building his own motorcycles using that Rotax mill. And so was born, the ATK motorcycle—first as hand-built, made to order bikes and later as production machines. He also built two stroke models including the 250, 260 and 406. These machines also used Rotax supplied engines. Can Am died, KTM designed their own engine but ATK and a handful of other manufacturers around the world continued to use the Rotax engines.

Through the mid 1990's, ATK went through some ownership shuffles (outlined in a politically correct manner on ATK's website). Eventually, Horst Leitner moved on to form American Dirtbike and a group of new investors owned the rights to the ATK name. With the new investors, the company was moved to Bountiful, Utah and headed up by Frank White. The influx of new cash and new blood brought new designs. The long-time alliance with KTM (supplier of most ATK suspension components and wheels) was broken. The decision to move to nicer, albeit more expensive Talon hubs was made. A number of suspension manufacturers have been used over the years including Paoli and WP (White Power—now ironically owned by KTM). Brakes were to remain the superb Brembo units. Domino controls, K&N air filters, Answer ProTaper handlebars and more, graced the new design. On the early WP forked models, the triple clamps were machined billet works of art with 'ATK' engraved on the front. On the later Paolli equipped bikes, they went to a more conventional triple clamp design. The four stroke models like my 605 were also available as a 350 and 500 though with the same lump of an engine. I understand that some did buy the smaller engined bikes to either compete in a certain class or to make it small enough to actually be possible to kickstart.

Perhaps the most amazing thing on the new design (which lasted from 1996 through 2003) was the single-sided frame. These photos don't show it clearly but the engine is a fully stressed member, common on street bikes but almost unheard of for an off road machine. The main backbone of the frame is an asymmetrical design with HUGE pipe running from the steering head down to the swingarm pivot. Just behind the steering head, it curves sharply to the left side of the bike. By the time it passes over the head, it is off to the left, leaving the top of the head completely exposed. So what? Wait until you go to adjust the valves on this thing. The rocker covers come right off and you are staring straight into the head. It is a dream to work on. The carburetor is similarly unencumbered and cable and electrical routing is ideal. With this huge backbone attached only to the cylinder head and one side of the swingarm pivot, the only purpose it serves is to hold the fork in place and provide a place to hold the oil. An added benefit of being the oil tank is that it is tall and slender (vertically speaking). Even if the owner is less than diligent about maintaining the oil level, the dry sump design and the slender oil reservoir do a great job of keeping the lifeblood supplied to the engine.

The swingarm is actually attached to the engine, though it looks like there is a frame down there. What appears to be the lower cradle of a conventional frame is actually nothing more than a place to bolt the footpegs and brake pedal. It is hanging off of the bottom of the engine and is merely along for the ride. If not for the rider, you wouldn't even need it. Out back, the linkless rear suspension uses one shock attached to the left side of the swingarm. The shock feeds its load into the aforementioned backbone tube. An all aluminum battery box / airbox assembly is welded to the rear subframe. Battery? Yes, this ATK was available with electric start (and most were purchased that way). The small penalty in weight more than offset its benefit in my eyes. I still can't kickstart this beast when its cold.

So how is it to ride? Well, the 600cc Rotax has much better low-end grunt than the LC4 equipped KTM's. It will literally chug along at idle, rolling up to the base of a hill and if you can find the traction, just crack the throttle and go...GRRRRRRRRRR....it will just drive its way up. I can't tell you how many times I've had to shut off mid-way up a hill to avoid something, then cranked it back open and the bike just continued on. For a dual-sport mount that borders on the edge of streetable, it is a great machine. I will admit that even with all the trick components, it is still a tad heavy (blame the dated but still potent 25 year old engine design for that). If I lived near tight, single-track, wooded areas, I'd get something lighter (like the new Canondale/ATK?). Still, it is an awesome desert mount.


In 2003, I took the bike on the LA to Barstow to Vegas dual sport ride. It ran flawlessly through both days. Many times I found myself coming up on a washout or gully with no time to brake. I whacked the throttle, pulled up on the front end and hoped for the best. The big ATK took it in stride every time. What I learned through those two days was that this bike rewards being ridden hard. At slower speeds, it's a bit rough around the edges compared to the refined feel of the XR650 Honda or similar big-bore dirt bikes. When you let it stretch its legs though, you are rewarded with an awesome experience.

Now I'm not going to tell you that this is the 'be-all' 'end-all' of motocross, enduro or cross country bikes. If you're REALLY, TRULY racing, you are probably better off with one of the highly strung KTM's like the 450 or 525. Who buys ATK? Well, if the Honda XR650 is too ordinary and the Suzuki DRZ400 is too slow, then you are probably the person who wants an ATK. ATK appeals to the aging baby-boomer, probably in his late 30s - early 40s. He has enough money to buy anything he wants. He wants something exotic, something fast and something he will have as much fun washing and maintaining as he does riding it. For that person, the ATK 605 is without peers. It is a Ducati for the dirt. Its air cooled engine means simple maintenance. The engine has been around since the dawn of time with a reputation for reliability. The frame is tough, the suspension is tough, the controls are first rate and you won't pass yourself 50 times out on the trail.


Like any motorcycle, the ATK 605 did have a number of weak spots, some of which were corrected over the years and some that were not:
This design—as fond as I am of it—has been replaced. Rotax announced the cancellation of production on the big four stroke engine in 2003. Without an engine, ATK would be in trouble. With the financial collapse of Canondale Motorcycles, ATK acquired the rights to build and continue development of their innovative engine. It was a good fit for ATK. It is an innovative design and gave them an engine when they so desperately needed one.

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