2003–2006 · Supermoto · Buyer's Guide
660 SMC (MY2003)
Kickstart-Only Track Weapon
The Machine's Character
The 660 SMC comes straight out of KTM's supermoto competition program, and it shows. You get a liquid-cooled 654 cc LC4 single, and very little else. There's no ABS, no traction control, no ride modes, and starting it is a kickstart ritual you have to learn. What makes this generation special is how little stands between you and the road. With 10.4 in (265 mm) of fork travel, 12.2 in (310 mm) at the rear and 17-inch street rubber, it's built for one thing: attacking bends. Almost nothing else on the road is this direct.
On paper, 33 hp and 32 lb-ft at 4,000 rpm look modest. On the road the torque arrives low and hard, and the chassis turns on command. Lean clearance is effectively unlimited, and the front end tells you exactly what the tire is doing. It's for experienced riders who want a raw tool and like working on their own bike, because the LC4 needs attention. Water pump seals weep, rocker bearings wear, jetting runs lean, and false neutrals show up when oil changes slip. With a 2.4 gal (9 L) tank and a 93 mph (150 km/h) top speed, it's no highway bike.
Hard Numbers
Spec sheets don't ride bikes, but they set the baseline.
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| Power | 33 hp (24 kW) @ 6,500 rpm |
|---|---|
| Torque | 32 lb-ft (43 Nm) @ 4,000 rpm |
| Displacement | 654 cc |
| Engine | Single-cylinder |
| Cooling | Liquid-cooled |
| Gearbox | 5-speed |
| Final drive | Chain |
| Front tire | 120/70-17 |
| Rear tire | 160/60-17 |
| Ground clearance | 11.4 in (290 mm) |
| Front travel | 10.4 in (265 mm) |
| Rear travel | 12.2 in (310 mm) |
| Seat height | 35.8 in (910 mm) |
| Fuel capacity | 2.4 gal (9 L) |
| Top speed | 93 mph (150 km/h) |
Equipment check
Chassis
- Rear Suspension Adjustable Standard
Known issues
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Water Pump Seal Failure
Coolant weeping from the weep hole is a common LC4 trait; if left unchecked, it can lead to oil contamination and overheating.
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Rocker Arm Bearing Wear
Top-end ticking or clatter can indicate worn cam follower bearings or rocker arms, requiring a refresh to prevent further engine damage.
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Crankshaft Bearing Rattle
Excessive crankcase tremor or rattling under load may signal the need for main bearing inspection, particularly on high-mileage examples.
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Carburetor Jet and Idle Problems
Many owners report rough running, idle fluctuation, and glowing headers, often traced to lean jetting or worn carburetor components like the pilot screw and idle jet.
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Gearbox False Neutrals
Under moderate load, gear engagement can be vague, with occasional false neutrals or gear jump, especially if oil changes have been neglected.
The Numbers Compared
Compare the technical specifications of the KTM 660 SMC with other bikes in its class.
Head-to-head: KTM 660 SMC vs. its rivals
Power
Torque
Displacement
Top speed
Seat height
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