2004–2017 · Supermoto · Buyer's Guide
The Indestructible City Carver
The XT660X puts Yamaha's liquid-cooled 660 cc single in a steel tube frame on 17-inch wheels. That is about as honest as a supermoto recipe gets. It makes 48 hp and 44 lb-ft, and it delivers them as a thick, throbbing shove rather than a high-rev scream. There is no ABS, no traction control and no ride modes. What you get is a tall, simple street machine with 7.9 in (200 mm) of travel front and rear and a huge amount of lean clearance. It earned its cult following by having real character without being fragile.
It rewards commitment on a flowing back road and shrugs off the city commute, and it ages the way a good single should. The engine feels unbreakable, servicing is straightforward, 54 mpg keeps running costs low, and the aftermarket is deep. This bike suits the rider who wants to grin on a back road on Saturday and have cheap, easy transport on Monday. The honest caveat: the fork has no adjustment at all and the rear shock only takes preload, the 34.4 in (875 mm) seat is tall, and early bikes have snatchy low-speed fueling that makes slow maneuvers jerky.
Spec sheets don't ride bikes, but they set the baseline.
| Power | 48 hp (35 kW) |
|---|---|
| Torque | 44 lb-ft (59 Nm) |
| Displacement | 660 cc |
| Engine | Single-cylinder |
| Cooling | Liquid-cooled |
| Gearbox | 5-speed |
| Final drive | Chain |
| Fork | Telescopic |
| Front brake | 320 mm |
| Front tire | 120/70-17 |
| Rear tire | 160/60-17 |
| Wheelbase | 58.5 in (1485 mm) |
| Ground clearance | 8.3 in (210 mm) |
| Front travel | 7.9 in (200 mm) |
| Rear travel | 7.9 in (200 mm) |
| Seat height | 34.4 in (875 mm) |
| Wet weight | 410 lb (186 kg) |
| Fuel capacity | 4.0 gal (15 L) |
| Fuel economy | 54 mpg (US) |
Equipment check
Chassis
Much of what I know about how the XT660X lives with its owners comes from years of listening: paddock talk, chats with owners, club-night conversation, and the messages riders send me directly. The picture is consistent. Owners love how little the bike asks of them and how it handles a twisty road. Their gripes center on low-speed manners and a few wear items.
Riders consistently describe a bike they can keep running themselves with basic tools. The single has a following among round-the-world travelers for soaking up big mileage and hard use. On twisty roads, owners credit the wide bars and quick steering for giving them plenty of confidence in corners.
The most common gripe comes at walking pace, where owners lean on the clutch and rear brake to smooth out an abrupt throttle. Worn cush rubbers show up as lash and a clunky feel in the driveline. Some owners also report factory bars that bend easily in a drop, often replaced with fatter aftermarket bars on risers. A few say the suspension goes soft and loses control on bumpy roads past about 18,600 mi (30,000 km).
Snatchy throttle / low‑speed fueling hesitation
The EFI mapping on early models causes an abrupt on/off throttle response, making slow manoeuvres jerky. Later models (2009‑on) received improved mapping, and aftermarket fueling modules can mitigate the issue.
Premature cush-drive rubber wear
The rear wheel cush-drive rubbers degrade prematurely, causing excessive driveline slack and clunky engagement. A cheap fix, but owners report needing replacement every 9,300–12,000 mi (15,000–20,000 km).
Regulator/rectifier failure
The charging system components can overheat or fail with age, leading to battery drain, poor starting, or a flat battery. Replacement rectifiers are readily available.
Cold‑start moisture in spark‑plug cap
After wet weather or a cold damp night, moisture can penetrate the spark‑plug cap, causing the engine to misfire or refuse to start. A spray of WD‑40 inside the cap usually cures it.
Where this Yamaha XT 660X 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 XT 660X is actually built for.
With 48 hp it won't win the long canyon straights. But the light steering and huge lean clearance make the tight sections a blast, and it copes with LA traffic on the way there.
Made for Angeles Crest Highway · Coronado Trail / US 191 · Highway 1 / Big Sur
If you're chasing cleaner lines rather than speed, this is a good teacher. It's light and tall with lean clearance to spare, and it's simple enough to let you focus on technique.
Made for Back of the Dragon · Blue Ridge Parkway · Cherohala Skyway
If this one isn't quite the fit, these are the bikes worth riding back-to-back against it.
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