KTM 640 Duke II

KTM Duke 640
Manufacturer	KTM
Also called	Duke II640, Duke II 640, 640 Duke, 640 Duke II Yellow - Black, 640 Duke II Black, 640 Duke II Red, 640 Duke II Limited Edition, 640 Duke II
Production	1998 - 00
Engine	Four stroke, single Cylinder. SOHC, 4 valves, engine balancer
Compression ratio	11.5:1
Top Speed	162 km/h / 101 mph
Ignition	Kokusan contactless DC-CDI ignition with advanced system
Spark Plug	NGK DRBEA
Battery	12V 8Ah, maintenance free
Transmission	5 Speed
Frame	Central chrome-moly steel frame
Suspension	Front: WP - 4054 Roma Top adjuster, preload, compression and rebound adjustable Rear: Central shock absorber WP IBS with PRO-LEVER linkage to rear- swing-arm with needle bearing
Brakes	Front: Single 320 mm disc, 4 piston caliper Rear: Single 220 mm disc, 1 piston caliper
Front Tire	120/70 - ZR17 58H
Rear Tire	160/60 - ZR17 69H
Wheelbase	1460 mm / 57.5 in
Seat Height	860 mm / 33.9 in
Weight	145 kg / 320lbs (dry),
Fuel Capacity	11.3 L / 3.0 US gal / 2.4 Imp gal
Manuals	Service Manual

It could reach a top speed of 162 km/h / 101 mph.

Engine

The engine was a Liquid cooled cooled Four stroke, single Cylinder. SOHC, 4 valves, engine balancer. The engine featured a 11.5:1 compression ratio.

Drive

Power was moderated via the Multi-disc in oil bath.

Chassis

It came with a 120/70 - ZR17 58H front tire and a 160/60 - ZR17 69H rear tire. Stopping was achieved via Single 320 mm disc, 4 piston caliper in the front and a Single 220 mm disc, 1 piston caliper in the rear. The front suspension was a WP - 4054 Roma Top adjuster, preload, compression and rebound adjustable while the rear was equipped with a Central shock absorber WP IBS with PRO-LEVER linkage to rear- swing-arm with needle bearing. The 640 Duke II was fitted with a 11.3 L / 3.0 US gal / 2.4 Imp gal fuel tank. The bike weighed just 145 kg / 320lbs. The wheelbase was 1460 mm / 57.5 in long.

Photos

Overview

KTM 640 Duke II

AN ANGUISHED HOWL OF RUBBER AGAINST PAVEMENT ECHOES off the surrounding buildings as the peculiar machine slows for a comer. Tail hung well out in a controlled brake slide as the fat rear tire scribes a dark arc deep into the apex. Confident in the bike's capability, the rider dials on the power and completes the corner in a crossed-up wheelie. A few more hot laps around the curbed islands and li, poles, and it's time to get out of Dodge before the sheriff arrives... Okay, so an occasional late-night romp through a vacant shopping-center parking lot may not be the most responsible two-wheeled behavior, but are we to blame for the company we keep? It's a classic case of guilt by association when a KTM Duke II is your accomplice. "Tlie bike made me do it, officer, honest."' Since its 1994 release, KTM's street-legal supermotard bike has amassed a reputation for pavement play. Talk to any sport rider who has crossed paths with one of these "Dukes of Hazard," and you'll likely hear tales of wild wheelies, eye-popping stoppies and an uncanny ability to gun down bikes twice its size in the twisties. Over the years, the Duke has grown increasingly popular, and has received minor updates, including an electric starter in '96, and 16cc of added displacement two years ago. With the Duke II comes further street refinement and new wrappings that keep step with the current styling of KTM's LC4 off-road models. Sharper-edged lines have replaced the rounded body contours of its predecessor, giving the Duke II a more compact and aggressive appearance. Viewed from the front, the vertically stacked projector-beam headlight array commands attention, resembling that of the Suzuki Hayabusa and Italian exotics such as the MV Agusta F4 and Benelli Tornado Tre.

Other updated bits include Italian-made BBS cast-alloy wheels in place of the previous wire-spoked Akronts. The front rim still measures 3.5 x 17 inches^, while the rear has grown .25-inch wider to 4.5 x 17 inches. Apart from their stylish looks-closely resembling BBS's race-car rims-the new wheels are tubeless. A stout, new 43mm WP inverted fork replaces the old Duke's 40mm legs, and there's a stiffer swingarm, too. A tush tuck has cleaned-up the Duke's tail, as the bike now shoots from both hips with dual muffler cans positioned, Ducati 996-style, beneath its seat. The double-barreled arrangement recalls the Vickers machine guns mounted on the business end of a Sopwith Camel. Backroad dogfighters beware! It may sound like tall talk coming from a rider astride a humble 626cc Single, but the Duke's off-road-bred chassis makes it a fierce scrapper on its home turf. Loads of cornering clearance, grippy Bridgestone BT93 Battlax radials, tractable power delivery and no small helping of attitude are the ingredients for setting a blistering pace through any tight series of switchbacks. And if the road surface suddenly rums bad, no problem-the Duke's suspension eats up bumps and potholes like few streetbikes can. Unlike a conventional long-travel dual-sport machine, the Duke II makes do with just 5.5 inches of front-wheel movement and 6.7 inches at the rear. With its spring and damping rates calibrated for road work, fore-and-aft chassis pitching is minimal. The only handling quirk we encountered was fair bit of fork dive when the front brake was suddenly applied while leaned over in a corner-not a recommended riding practice by any means. But when it comes to dealing with a dicy situation, the Duke II has the instincts of a cat. The wide Magura tapered-aluminum handlebar and dirtbike-inspired riding position instill an uncanny sense of control when ridden to the limit, even over the roughest pavement. And wet road conditions? Pour it on! As for negotiating urban traffic, riding the KTM is like having the keys to the city. Its 35-inch-high seat provides a clear line of sight over the tops of cars, yet it's low enough for riders of average inseam to find a firm footing at stops. And the bike's light weight, coupled with torque-rich power delivery right off the bottom, gets the drop on the rush-hour rat race every time. Ride a Duke about town for long, and you begin to perceive your environment differently. A raised manhole cover is no longer an obstacle to avoid, but a chance to catch some free air! Ditto for speed bumps or sudden elevation changes. Low-traction surfaces add another fun element to any urban hard-cross course. Pulling wheelies is simply a matter of rolling on the gas in low gear or snapping the throttle open along with a light tug on the bar in second. True, the KTM is no match for multi-cylinder sportbikes in straight-line acceleration, but among its one-lunged peers, the Duke makes no apologies. Its liquid-cooled, four-valve, four-stroke engine churned out 49 horsepower and 42 foot-pounds of torque on CfFs rear-wheel dyno. Accelerating through the slick-shifting five-speed gearbox is swift and effortless, evidenced by its 99-mph quarter-mile trap speed and gearing-limited, 108-mph top speed. At freeway speeds, there is more than enough juice in reserve to cleanly pull roll-on passes without kicking it down a gear. A gear-driven counterbalancer helps keep engine vibes at an acceptable level. At lower revs, the power pulses are soul-stirring, but as engine speeds exceed 5000 rpm-an indicated 75 mph in top gear-a high-pitched buzz develops, making long freeway hauls taxing. The stylish mirrors provide very good views to the rear, but are inflicted with a healthy buzz. A good practice is to periodically pull in the clutch and let the revs fall to idle, and then check your mirrors for the fuzz. In fact, hanging onto your driver's license is quite probably the greatest challenge you'll face as a Duke II owner. While speeding citations are the bane of any sport rider's existence, Duke riders are just as likely to rack up "exhibition of speed" or "reckless driving" charges. Best of luck with the-Duke-made-me-do-it defense. If all else fails, plead insanity. S Source Cycle World 1999

Make Model	KTM 640 Duke II
Year	1998 - 00
Engine Type	Four stroke, single Cylinder. SOHC, 4 valves, engine balancer
Displacement	624.6 cc / 38.1 cu in
Bore X Stroke	101 x 78 mm
Compression	11.5:1
Cooling System	Liquid cooled
Lubrication	2 x Eaten oil pumps
Induction	Mikuni BST 40 carburetor
Ignition	Kokusan contactless DC-CDI ignition with advanced system
Starting	Electric & kick
Spark Plug	NGK DRBEA
Battery	12V 8Ah, maintenance free
Max Power	40.1 kW / 55 hp @ 7000 rpm
Max Torque	60 Nm / 6.1 kgf-m / 44.3 lb-ft @ 5500 rpm
Clutch	Multi-disc in oil bath
Transmission	5 Speed
Primary Drive Ratio	30:81, straight cut gears
Gear Ratios	1st 14:35 / 2nd 15:24 / 3rd 18:21 / 4th 20:19 / 5th 22:18
Final Drive Ratio	17:38
Final Drive	Chain, O-ring 5/8 x 1/4"
Frame	Central chrome-moly steel frame
Front Suspension	WP - 4054 Roma Top adjuster, preload, compression and rebound adjustable
Front Wheel Travel	140 mm / 5.5 in
Rear Suspension	Central shock absorber WP IBS with PRO-LEVER linkage to rear- swing-arm with needle bearing
Rear Wheel Travel	170 mm / 6.7 in
Front Brakes	Single 320 mm disc, 4 piston caliper
Rear Brakes	Single 220 mm disc, 1 piston caliper
Front Tire	120/70 - ZR17 58H
Rear Tire	160/60 - ZR17 69H
Steering Head Angle	62.5o
Wheelbase	1460 mm / 57.5 in
Ground Clearance	250 mm / 9.9 in
Seat Height	860 mm / 33.9 in
Dry Weight	145 kg / 320lbs
Gvwr	350 kg / 773 lbs
Engine Oil Capacity	2.2 L / 2.3 US qt / 1.9 Imp qt
Fuel Capacity	11.3 L / 3.0 US gal / 2.4 Imp gal
Standing ¼ Mile	12.5 sec
Top Speed	162 km/h / 101 mph