| Specification | Value |
|---|---|
| Production Years | 2004-2006 |
| Engine Oil | SAE 10W-40 (JASO MA) – 2.6 L |
| Front Tire | 120/70 R17 M/C (58H) |
| Rear Tire | 160/60 R17 M/C (69H) |
| Tire Pressure | F: 2.0 bar / R: 2.0 bar |
| Battery Type | GT9B-4 |
| Spark Plug | NGK CR7E (0.7-0.8 mm gap) |
The Yamaha XT 660 X (DM014) holds a unique place in motorcycling history as one of the first mass-produced motorcycles to successfully bridge the gap between rugged enduro heritage and aggressive urban supermoto styling. Unlike its predecessor, the XT600, the DM014 introduced a sophisticated dry-sump lubrication system where the oil is stored within the frame down-tube, an engineering choice that allowed for a slimmer engine profile and improved cooling efficiency.
Technical Engineering & Performance
At the heart of the DM014 is a liquid-cooled, 660cc single-cylinder engine featuring electronic fuel injection—a significant technological leap for the XT series in 2004. This powerplant delivers a punchy torque curve ideal for urban environments. The chassis is specifically tuned for 17-inch Excel rims, distinguishing it from its dual-sport sibling (the XT660R) with a stiffer suspension setup and a massive 320mm Brembo front brake disc for superior stopping power.
Maintenance Guide: Keeping the DM014 Prime
Lubrication System
The dry-sump system requires precise measurement. Always check the oil level after the engine has reached operating temperature and has been idling for several minutes. Use 2.6 liters of SAE 10W-40 meeting JASO MA standards to ensure clutch longevity.
Ignition and Electrical
For optimal combustion, the NGK CR7E spark plug must maintain a gap of 0.7-0.8 mm. The electrical system relies on the GT9B-4 battery; given the high-compression nature of the single-cylinder engine, maintaining a healthy cold-cranking amperage is vital for reliable starting.
Tires and Handling
The XT 660 X is sensitive to tire pressure. To maintain the flickable nature of the supermoto geometry, keep both the 120/70 front and 160/60 rear tires at 2.0 bar (29 psi). Lower pressures may lead to sluggish steering, while higher pressures can compromise the contact patch during aggressive lean angles.
Expert Verdict
The DM014 is a robust, over-engineered machine that rewards regular maintenance with bulletproof reliability. Its transition from the trail to the tarmac was not just a cosmetic change but a fundamental re-engineering of the XT platform, making it a modern classic in the supermoto category.