2002–2007 · Enduro · Buyer's Guide
The Off-Road Single That Bites
The 640 LC4 Enduro is a dual-sport that puts the dirt first and doesn't apologize for it. A 625 cc liquid-cooled single making 54 hp and 41 lb-ft sits in a steel double-cradle frame. WP suspension is fully adjustable at both ends, with an upside-down fork giving 11.0 in (280 mm) of travel and a monoshock giving 12.6 in (320 mm). Add 12.2 in (310 mm) of ground clearance, a 21/18-inch wheel pair and 348 lb (158 kg) wet, and you have a big single built to cover rough ground. Rideability counts for more than peak power here. The engine pulls hard from low revs and still has some zing near the top.
It rewards skilled riders and doesn't carry anyone else. There's no ABS, no traction control and no ride modes. You get a throttle, a clutch and a chassis that expects you to know what you're doing with them. A center stand comes standard, which helps with chain and tire work at the trailhead. Ownership takes attention. The water pump seal can leak coolant into the oil, so check for milky oil. The carb setup can make hot restarts stubborn. The 2002 and 2003 bikes fall inside the front-spoke recall window, and early units carried the ball-type mainshaft bearing. Buy on service history, not shine.
Spec sheets don't ride bikes, but they set the baseline.
| Power | 54 hp (40 kW) @ 7,000 rpm |
|---|---|
| Torque | 41 lb-ft (55 Nm) @ 5,500 rpm |
| Displacement | 625 cc |
| Engine | Single-cylinder |
| Cooling | Liquid-cooled |
| Gearbox | 5-speed |
| Final drive | Chain |
| Fork | Upside-down (USD) |
| Front brake | 300 mm |
| Front tire | 90/90-21 |
| Rear tire | 140/80-18 |
| Ground clearance | 12.2 in (310 mm) |
| Front travel | 11.0 in (280 mm) |
| Rear travel | 12.6 in (320 mm) |
| Seat height | 37.0 in (940 mm) |
| Wet weight | 348 lb (158 kg) |
| Fuel capacity | 3.2 gal (12 L) |
Equipment check
Chassis
What follows comes from years of listening: paddock talk, owner chats, club-night conversations and the messages riders send me directly. For the 640 LC4 Enduro the pattern is clear. Owners praise how it behaves once the trail turns rough, and their gripes center on height, buzz and upkeep.
Riders bring up the suspension first. They describe damping that stays plush but controlled over rocks and roots, and a chassis that holds a precise line through corners. The engine gets equal credit. Owners say it pulls all the way to the redline and answers the throttle crisply, in tight terrain and on open stretches alike.
Shorter and less experienced riders say it's hard to dab a foot in technical sections, and that costs them confidence. Owners also say the vibration is harsher than on many rival dual-sports once the road stretches get long. Leaks come up again and again. Owners name the countershaft sprocket and rocker cover as places where it weeps, so regular inspection is part of owning one. A few add that hot restarts drag on unless you follow a precise starting routine.
Front wheel spoke loosening (2001‑2003)
On 2001-2003 models, spokes could loosen, potentially puncturing the inner tube. A recall was issued; some bikes received new wheels or spoke clamps.
Mainshaft bearing failure (pre-2003)
Early models used a ball bearing on the output shaft that could fail, causing transmission noise and eventual seizure. Upgraded to a roller bearing from 2003 onward.
Water pump seal failure
The mechanical seal behind the water pump impeller can leak coolant into the oil, often noticed as milky oil or external weepage.
Hard starting when hot (carburetion)
Carb tuning can lead to difficulty restarting a hot engine, especially after stalling; often improved by jetting changes or careful starting technique.
Where this KTM 640 LC4 Enduro pulls ahead of — or falls behind — its rivals on the numbers, and the typical bike in its class on character.
Power
Torque
Displacement
Wet weight
Seat height
Forget spec-sheet bragging. Here's who the 640 LC4 Enduro is actually built for.
This is your bike. It's narrow, has plenty of clearance and fully adjustable suspension, and the single's low-rev pull suits technical desert climbing. Pack water, though, because the tank only holds 3.2 gal (12 L).
Made for Bar M / Kane Creek · Imperial Sand Dunes · Johnson Valley OHV Area
It'll handle the rough BDR sections easily, but plan around a 3.2 gal (12 L) tank, a firm seat and a lot of vibration on long connecting roads. It suits riders who put the dirt ahead of comfort.
Made for AZBDR — Arizona Backcountry Discovery Route · California BDR South · COBDR — Colorado Backcountry Discovery Route
If this one isn't quite the fit, these are the bikes worth riding back-to-back against it.
