Tracing the Lineage of the Atk 560
TRACING THE LINEAGE OF THE ATK 560
Anatomy of a winner
SOME MOTORCYCLES ARE WINNERS, AND SOME riders are winners. When two winners team up, history usually is made. The particular ATK 560 that CYCLE WORLD entered in this year's CMC Four-Stroke Championship was a winner, and it had a history of being with riders of the same sort.
It all began when Brian Myerscough rode that very ATK in the Four-Stroke Nationals at Carlsbad in 1985, scoring an overall win. Then Steve Ekiund rode it in ABC's Superbikers event and won his semi. Months later, former motocrosser Warren Reid entered the same machine in the Ascot TT National, his first-ever Camel Pro Race. He took second in his semi and 13th in the main-an unheard-of performance for a first-timer. And finally, Doug Dubach rode this same machine in the Open Pro class at this year's Four-Stroke Championship and won both motos.
How can one bike be competitive in so many differ ent kinds of racing? That's what we wondered, so we asked Horst Leitner. the bike's designer and builder, to demonstrate what he does to convert the bike from its stock motocross form into a dirt-tracker/Superbiker machine. And we were shocked to learn that the whole process takes less than 20 minutes, consisting of nothing more than wheel changes-from a 21-inch front and an 18-inch rear to a pair of 1 9-inchers---and the switch to a shorter shock. That's it.
Of course, the bike that Leitner starts with isn't quite your ordinary, garden-variety motocrosser. it's a $4300, hand-built four-stroke with some very unusual features. The particular bike we rode had a ported head and an experimental exhaust, but otherwise was a standard ATK.
On the other hand, there's nothing really "stan dard" about any ATK. For starters, the rear disc brake is mounted on the transmission countershaft instead of on the rear wheel. With such a design, the entire package is lighter, the need for a complicated full floating rear-brake linkage is eliminated, and wheel removal is simpler. In addition, the ATK has a single shock that is mounted, sans linkage, on one side of the swingarm. BMW-style. The bike also uses Leitner's A Trak chain-torque-elimination device that keeps the chain parallel to the swingarm. and a White Power upside-down front fork. To top it all off, the bike is powered by a sohc, 562cc Austrian Rotax engine
What really sets the ATK apart from any other pro duction motocrosser, though, is the attention to detail Leitner has given it. Ever had air build up in your fork? On the ATK, relieving that pressure is as easy as pressing a button atop of each fork leg. And if you've ever struggled with rear-wheel spacers after changing a tire, you can appreciate the ATK's rear wheel, which use no spacers whatsoever. The same philosophy holds true for removing the rear shock: You just undo two bolts and pull. In fact, maintenance on the ATK is so simple that Joe Coppege was able to take a nearly stock `85 model to last year's International Six-Days Enduro in Alp, Spain. and survive the ordeal well enough to bring home a bronze medal.
En~duros, T~s, motocross, the Superbikers-not many ordinary machines are capable of those kind of extremes. But very little about the ATK is ordinary, from its performance to its price tag. The ATK isn't for ordinary riders; it's for those who taking winning very seriously. -Ron Lawson
