KTM Duke II 640: specifications and compatible accessories
The supermotard that created the Duke range
Single-cylinder LC4, 17-inch wheels and no frills: the Duke II is the motorcycle from which the entire current Duke family descends. Today it is a motorcycle for enthusiasts, and the catalog reflects that — just one dedicated accessory, in three finishes.
- In summaryRecent classic motorcycle: the catalog includes the essentials, as stated by the manufacturer.
- AvailableFront fender extension, in three finishes.
- SharedThe same part number applies to the SD 990 through 2006.
- For the restUniversal accessories: mirrors, soft luggage, motorcycle cover.
- BrandsR&G, LOBOO, Endurrad.
Technical specifications
| Engine | Single-cylinder liquid-cooled LC4, 625-640 cc |
|---|---|
| Power | approximately 50 hp depending on the specification |
| Transmission | 5 or 6 gears depending on the year, chain final drive |
| Chassis | Steel trellis frame, inverted WP fork |
| Wheels | 17-inch front and rear |
| Weight | approximately 155 kg dry |
| Seat height | 860 mm |
| Production | 1999-2006, the origin of the Duke range |
Pros and cons
Pros
- Very lightweight and fun in tight corners
- Simple mechanics, with no electronics
- Growing collector value among enthusiasts
- Universal components that are easy to adapt
- Good-quality WP suspension as standard
Cons
- Only one dedicated accessory in the catalog
- Pronounced single-cylinder vibrations
- Limited range and minimal comfort
- Genuine spare parts increasingly difficult to find
- Frequent maintenance on high-mileage examples
What to fit
For a twenty-year-old motorcycle, the dedicated catalog is what it is. Below you’ll find what the manufacturer lists, plus the universal parts that work.
- 1
Front fender extension, blackListed for the Duke II 640 and SD 990 through 2006: protects the radiator and engine from splashes. - 2
Fender extension, clear versionSame part, clear finish: blends better with light-colored fenders. - 3
Folding mirrorsOn a vintage motorcycle, replacing broken mirrors with originals is difficult: these fit the standard thread. - 4
Mirror adaptersNine mounting codes: they solve the problem when the original thread does not match that of the new mirror. - 5
Vintage 3.5-liter tank bagIn canvas and leather: the only luggage solution consistent with this motorcycle's aesthetics. - 6
Waterproof motorcycle coverOn a motorcycle you keep for years, it protects the plastics and seat from the sun, which fades them.
Compatibility table
The Duke II shares nothing with modern Dukes: same name, different motorcycles.
| Accessory | SD 990 up to 2006 | Modern Dukes, 390-890 |
|---|---|---|
| Fender extension | yes | no |
| Engine protection and sliders | no | no |
| Mirrors and adapters | yes | yes |
| Tank bags and soft luggage | yes | yes |
| Motorcycle cover | yes | yes |
Brands with dedicated accessories
R&G RacingThe only dedicated oneFront fender extension in three finishes, also listed for the SD 990 up to 2006.
LOBOOUniversals that workFolding mirrors, adapter kits, and tank bags in small sizes.
Frequently asked questions
Why are there so few accessories?
Because the motorcycle has been out of production since 2006 and the aftermarket follows sales volumes. What remains is the essentials declared by the manufacturer, plus universal accessories that fit any motorcycle.
Do accessories for modern Dukes fit the Duke II?
No. The current Dukes, from the 390 to the 890, share nothing with this motorcycle apart from the name: the frame, engine, and mounting points are completely different.
Are the three fender extensions different products?
No, it is the same part in three finishes: black, clear, and the version with the Endurrad logo. Only the appearance changes.
What can I install to protect it?
We do not have dedicated engine sliders or engine protection for this model. If you need them, write to us indicating the year: we will check with our suppliers whether a code is still available.
Is it worth keeping?
It is a motorcycle that is gaining interest among enthusiasts, precisely because it is the ancestor of the Duke range. The limitation is the availability of original spare parts, not the mechanics.