ATK 605

From CycleChaos
Jump to navigation Jump to search


1996 ATK 605.jpg
ATK 605
Manufacturer
ATK
Production 1992 - 1998
Class Enduro
Engine
air-cooled, four-stroke, Rotax single cylinder, DOHC, 4 valves
Bore / Stroke 96.5mm x 96.5mm
Compression ratio 9.5:1
Top Speed 98 mph
Transmission Gear box: 5-speed, manual

Final Drive: chain

Clutch: wet multi-disc, manual
Suspension Front: 40mm WP upside-down telescopic fork
Rear: monoshock
Brakes Front: single 260mm disc, 2-piston caliper, Brembo
Rear: single 220mm disc, Brembo
Front Tire 80/100-21
Rear Tire 110/100-18
Seat Height 36.5 inches (927 mm)
Weight 129.0 kg (wet)
Manuals Service Manual


The ATK 605 was a air-cooled, four-stroke, Rotax single cylinder, DOHC, 4 valves Enduro motorcycle produced by ATK between 1992 and 1998.

Engine[edit | edit source]

A 96.5mm bore x 96.5mm stroke result in a displacement of just 598.0 cubic centimeters.

Drive[edit | edit source]

The bike has a 5-speed, manual transmission. Power was moderated via the wet multi-disc, manual.

Chassis[edit | edit source]

It came with a 80/100-21 front tire and a 110/100-18 rear tire. Stopping was achieved via single 260mm disc, 2-piston caliper, Brembo in the front and a single 220mm disc, Brembo in the rear. The front suspension was a 40mm WP upside-down telescopic fork while the rear was equiped with a monoshock.

Overview[edit | edit source]

ATK's new 605 Thumper and its revolutionary single-sided frame had passed the extreme flex test. It is hard to comprehend how a frame that connects the headset with only the lower-left swingarm pivot could possibly be as rigid as an ordinary frame, but it is. And that's only the beginning: Its design also allows a full 13.2 inches of rear-wheel travel, but with a relatively low 36.5-inch seat height. Plus, it's 10 pounds lighter than the conventional frame it replaces. More oddities: The detachable lower frame rails and footpegs are divorced from the main frame and bolt on via the lower engine mounts; a skidplate smooths the transition from a dead-end front downtube to the separate lower cradle, creating a tunnel for the left-side header pipe to pass through.

It is not at all strange for ATK to debut a revolutionary new concept on a motorcycle. Remember the company's A-trak chain-torque eliminator, from which the ATK name was derived? How about the countershaft-mounted disc brake? Those ideas worked on paper, but real-world conditions forced ATK back to more normal setups.

That should not be a problem with this new frame. The heart of the 605, its 598cc Rotax motor, is about as tried and tested as anything on two wheels. It's ancient by today's two-years-and-you're-out standards, but it truly pulls its own weight-all 100 pounds of it. Feeding the motor is a 40mm Dell'Orto round-slide carburetor breathing through a K&N fabric air filter. The new airbox is actually an integral part of the all-aluminum rear subframe.

A completely redesigned stainless-steel exhaust pipe gets the gasses out with less restriction and flows through a large-core muffler capped off with SuperTrapp discs.

WP continues to produce suspension for ATK. The 40mm inverted fork has full adjustment, this year with compression in one leg and rebound in the other. As per usual ATK practice, the side-mounted WP shock is progressively valved and runs without a linkage. After years of borrowing bodywork from other brands, ATK went big this year and produced its own sidepanels, giving the bike a distinct look.

The fuel tank is designed to call attention to the new frame, and houses a claimed 3.6 gallons. The fenders and numberplate are still sourced from Italian plastic maker UFO. Also on the thumbs-up list is the new oversized front-brake rotor squeezed by a Brembo dual-piston caliper; much improved over last year, though still a notch off Honda's class-leading stopper. Depending on the model choice, starting is simple. With either the delicate push of a button or the swift swing of a kick starter, the 605 will fire right up, even on a brisk, 30-degree Utah morning.

Though in the past Rotax motors have been finicky about starting, the spot-on jetting of the ATK sorts this out. Warm-up is quick-no coolant to heat here. Small-handed riders will find the reach to the clutch lever excessive, but everyone will appreciate the light pull and smooth engagement. The transmission gives a solid feel and shifts respectably, though the throw may be a bit long for those used to Japanese machinery. Spread of the wide-ratio five-speed will suit everything from tight single-track rock climbing to cruising comfortably at 65 mph on the interstate.

ATK 605


A wide powerband is one of the ATK's joys. Torque is abundant, throttle response instant. It runs like a well-tuned Honda XR600, but with a much smoother bottom-end power spread. The slow-revving nature of the motor is deceiving, but ground speed tells the real story—the 605 simply ingests off-road miles. There's really no need to rev the motor, but the fact that you can shows its versatility. Suspension settings are the same on all of ATK's

Thumpers. Because the dual-purpose model makes up 95 percent of ATK big four-stroke sales, it comes as no surprise that the settings cater to fireroads more than supercross-style double-jumps. If your riding taxes the suspension, or the terrain gets nasty, the suspension has enough adjustment to handle the situation. During our visit to ATK's headquarters in Bountiful, Utah, I raced a kick-start version with stock suspension in a national hare & hound, and it worked admirably, rarely bottoming.

So, back to this half-a-frame concept. Riding the bike, you would never know that there is some weird, new-fangled frame beneath you. Made up of large diameter, thin-walled tubing, it resembles half a perimeter-style frame, but seems amazingly rigid. The wrapped-steel swingarm, just like the one on the two-stroke LQ model, is much stronger than the ol"d rectangular unit, and does its share to reduce flex, too.

1994 ATK 605


The frame also carries the bulk of the engine's 3 quarts of oil. This feels great on a cold day, but the heat can get to a sit-down rider's left thigh in warmer conditions. ATK has, however, taken precautions: The fuel tank has threaded inserts to allow the mounting of a heat shield. The electric-start 605 does not mask its claimed 280 pounds (260 for the kick-start model). On the plus side, the weight is well centered and low. Stability is great and we never experienced any headshake. Quick side-to-side turns require an average amount of effort, on par with most big Thumpers. Sliding has never been easier, the low seat height allowing you to really get "into" the bike while hacking the back end out.

There is plenty of room to move about on the ATK. A long and spacious seat, and its relationship to the footpegs does not cramp even tall riders. Ground clearance is not an issue, with 13 inches before a frame rail touches down. Glitches? Some, and here is where we, and anyone SI Buell Solo Saddle SI Buell Solo Saddle Doubles Seating Area. Finely Crafted. Uses Stock Screw Fitting. Meant For Solo Rider. #Sl $269. Corbin spending close to $8000 on a dirtbike, deserve to be critical—the finer points. We will always praise ATK's use of high-quality chains, handlebars, billet triple-clamps and hubs, and you get some of the best rims, spokes, sprockets, air filters and rotors on the market.

But it's small details that hurt the ATK: a flimsy aluminum plate that supposedly protects the chain guide, but bends when pebbles hit it; footpegs that are plenty strong and functional, but become dirt scoops on contact with the ground; a flappy-flyer license-plate mount that interferes with the tire. Sure, dirt riders love to tinker with their bikes, but for this many dollars, they shouldn't have to. Still, ATK has a great product here, in need of just a bit more polishing in a few areas. For the deep-pockets dual-purpose rider in search of a unique, innovative, exciting ride, ATK's new 605-strange frame and all-is up to speed and ready to rip.

Make Model ATK 605
Year 1992
Engine Air cooled. four stroke. single cylinder. DOHC. 4 valves per cylinder
Capacity 598
Bore x Stroke 97 x 81 mm
Compression Ratio 9.5:1
Induction 40mm Dell\'Orto
Ignition / Starting
Max Power
Max Torque
Transmission / Drive 5 Speed / chain
Front Suspension
Rear Suspension
Front Brakes Single 260mm disc
Rear Brakes Single 220mm disc
Front Tyre 80/100-21
Rear Tyre 110/100-18
Dry-Weight 129 kg
Fuel Capacity 16.5 Liters

1992 ATK 605[edit | edit source]

The 1992 MY ATK 605 has, at its heart, an air-cooled, four-stroke, 598cc, Rotax single cylinder engine paired to a five-speed manual transmission. It comes standard with features such as a 40mm WP upside-down telescopic fork, a monoshock rear suspension, a race-inspired livery, laced wheels with off-road tires mounted on them, a Brembo braking system with front and rear discs, a high-mounted exhaust, an analogue instrument cluster and a single seat.


1993 ATK 605[edit | edit source]

The 1993 MY ATK 605 is a powerful off-road machine that mainly addresses those riders who want more power to overcome even the most treacherous enduro track. It comes standard with features such as a single seat, laced wheels with knobby tires mounted on them, an analogue instrumentation panel, a Brembo braking system with front and rear discs, and a 40mm WP upside-down telescopic fork.

In the tech/engine department, it sports an air-cooled, four-stroke, 598cc, Rotax single cylinder powerhouse paired to five-speed manual transmission.


1994 ATK 605[edit | edit source]

The 1994 MY ATK 605 has, at its heart, an air-cooled, four-stroke, 598cc, Rotax single cylinder powerplant paired to a five-speed manual transmission. The American engineers have designed this two-wheeler especially for those riders who make zero compromises when it comes to power.

Standard features include a 40mm WP upside-down telescopic fork, an adjustable monoshock as a rear suspension, a high-mounted exhaust system, a race-inspired livery, an analogue instrument panel, a single seat and a Brembo braking system with front and rear discs.


1995 ATK 605[edit | edit source]

If you are on the market for a no-compromise off-road machine, then the 1995 MY ATK 605 may just be the right choice for you. It boasts a number of race-derived parts as standard, such as, a 40mm WP upside-down fork as a front suspension and Brembo braking system with front and rear discs, ensuring it can tackle even the most hardcore of enduro tracks.

In addition, sufficient grunt is ensured by its air-cooled, four-stroke, 598cc, Rotax single cylinder powerhouse, paired to a five-speed manual transmission.


1996 ATK 605[edit | edit source]

The 1996 MY ATK 605 is a powerful off-road two-wheeler, that offers plenty of grunt to overcome any enduro track out there from its air-cooled, four-stroke, 598cc, Rotax single cylinder powerhouse, paired to a five-speed manual transmission.

Also, it boasts race-derived features such as a 40mm WP upside-down fork and a Brembo braking system with front and rear disc brakes. Other features, such as the single seat, the analogue instrument cluster, the high-mounted exhaust and the racey livery only add to the desirability of this machine among ATK fans, and not only.


1997 ATK 605[edit | edit source]

1997 ATK 605 1997 ATK 605

The 1997 MY ATK 605 has, at its heart, an air-cooled, four-stroke, 598cc, Rotax single cylinder powerhouse paired to a five-speed manual transmission. Standard features for this machine include a race-inspired livery, an analogue instrument cluster, a single seat, a high-mounted exhaust, a Brembo braking system with front and rear disc brakes, and a suspension package composed of a rear monoshock and a front 40mm WP upside-down fork.


1998 ATK 605[edit | edit source]

1998 ATK 605 1998 ATK 605

The 1998 MY ATK 605 is a powerful off-road machine, suitable for those riders who make zero compromises when it comes to grunt. It sports an air-cooled, four-stroke, 598cc, Rotax single cylinder powerplant paired to a five-speed manual transmission.

The key features for this machine would be the 40mm WP upside-down telescopic fork coupled to a rear monoshock suspension, a Brembo braking system with front and rear discs, an analogue instrument cluster, a single seat, a bold livery and paint scheme and laced wheels with off-road tires mounted on them.


Videos[edit | edit source]