KTM 640 LC4 Supermoto (1998-2007)

The KTM LC4 640 is KTM’s popular supermoto stalwart – a rough, tough bugger that’s a capable commuter, trackday sleeper and friend to the wannabe stunt monkey. It sits on the civilized side of the LC4 family, benefiting from an anti-vibe damper, and an electric start to complement the kicker. Like all supermotos it’s as cheap as chips, geared for giggles and ready to rumble.

Engine

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This KTM 640 LC4 Supermoto's liquid-cooled, SOHC single-cylinder motor has been in KTMs for over a decade, and in the 640 it’s definitely as its most civilised. But if you’re new to the world of supermoto you’ll probably think it rough and vibey. They’re all like that, Sir. Unlike the spunkier SMC range, which flat-slide carbs, the 640 gets a 40mm CV item for a more user-friendly response, especially around town.

Ride and Handling

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Providing it’s not still sitting on the dreadful Pirelli MT60 tyres it comes with the KTM 640 LC4 Supermoto handles sharply. The fully-adjustable WP suspension and four-piston Brembo brakes mean confident stopping is just a two-finger tug away. The seat is narrow to let you climb over the bike for faster cornering, but you’ll be thankful for the small tank and the chance to get off after just 70-odd miles.

Equipment

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Apart from top names like Brembo and WP which adorn the stock machine the aftermarket offers a virtually unlimited opportunity to screw every last ounce of power from your KTM 640 LC4 Supermoto. A rear wheel dyno figure of 60bhp is well within reach.

Quality and Reliability

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The KTM 640 LC4 motor is extremely reliable, providing it’s serviced regularly. Every 3000 miles there are two oil filters to change, but that’s a 30-minute job. Change the oil, too – that takes about another 20 minutes, but those chores will keep the motor perkier for much longer. Adjusting the valve clearances is easy thanks to a simple screw and nut arrangement. Keep the 640 away from salted roads – or else it corrodes like hell.

Value

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The KTM 640 LC4 Supermoto is very good to buy, rubbish to sell. Supermotos are a poor monetary investment.

Model History

1998: Model released.
2005: Gets a twin pipe exhaust.
2007: KTM 640 LC4 Supermoto deleted.

Other Versions

KTM 660 SMC: No e-start, vibes aplenty, huge power, lighter weight, much shorter service intervals. Huge fun.

Specifications

Top speed	110 mph
1/4-mile acceleration	14.7 secs
Max power	53 bhp
Max torque	41 ft-lb
Weight	149 kg
Seat height	910 mm
Fuel capacity	9 litres
Average fuel consumption	42 mpg
Tank range	80 miles
Annual road tax
Insurance group	11 of 17

Engine size	625 cc
Engine specification	4v single, 5 gears
Frame	Tubular steel cradle
Front suspension adjustment	Preload, compression, rebound
Rear suspension adjustment	Preload, compression, rebound
Front brakes	Single 320mm disc
Rear brake	220mm disc
Front tyre size	110/90 x 17
Rear tyre size	160/60 x 17