The Bestem carbon fiber sprocket cover for the Aprilia RS 660 is a direct bolt-on replacement for the factory plastic cover on 2021–2023 RS 660 and Tuono 660 models. It is built from 100% pre-preg Toray carbon fiber, autoclave-cured in matched-metal molds, and finished with a proprietary UV-resistant clear coat backed by a lifetime warranty against sun-ray yellowing.
What does a sprocket cover do on the Aprilia RS 660?
The sprocket cover sits over the front drive (countershaft) sprocket on the left side of the engine. Its job is to keep road debris away from the chain and sprocket, contain chain-lube fling, and shield the rider if a chain ever fails. From the factory, Aprilia fits a plastic cover — functional, but it scuffs, dulls, and looks out of place next to the RS 660's sharp bodywork.
Why upgrade the stock RS 660 sprocket cover to carbon fiber?
- Rigidity: a pre-preg carbon laminate is far stiffer than injection-molded plastic, so the cover holds its shape and sits flush against the engine cases.
- Appearance that lasts: the twill weave ties in visually with other carbon parts on the bike — heel guards, hugger, chain guard — instead of a scuffed black plastic panel.
- Weight: the stock plastic piece is already light, so this swap is about quality rather than gram-counting. You still shave weight, but the real gain is a part that looks right and stays that way.
- Fitment accuracy: because the cover is molded in matched-metal tooling, the mounting holes land exactly on the factory bosses — no drilling, no trimming, no forcing fasteners.
Do carbon fiber parts turn yellow in the sun?
Yes — sun-ray (UV) yellowing is the single most common defect riders see on carbon fiber parts. Riders ask it constantly: "do carbon fairings turn yellow?" and "how long before carbon fades?" The clear coat on a standard carbon part — including OEM carbon — typically begins to amber and cloud at around 1,000 hours of UV exposure.
Bestem addresses this directly with a proprietary UV-resistant clear coat engineered specifically to protect the carbon weave, rated to approximately 3,000 hours of UV resistance — roughly 3× longer than the ~1,000 hours of standard OEM clear coat. Because of that coating, this sprocket cover carries a lifetime warranty against sun-ray (UV) yellowing. The part lives inches from a chain that gets cleaned and re-lubed constantly, in full sun on every ride — the coating is what keeps the weave looking new under those conditions.
How is the Bestem sprocket cover made?
Every Bestem part starts as 100% pre-preg Toray carbon fiber — fabric with resin pre-impregnated at a controlled ratio, not resin brushed on by hand. The layup is cured in an autoclave under heat and pressure, which consolidates the laminate and minimizes voids, and it is molded in matched-metal tooling rather than hand-laid, wet-lay, or resin-infused in a single-sided mold. That is an aerospace-grade process: it produces consistent wall thickness, accurate mounting points, and a clean weave on both faces of the part.
This is the same autoclave-cured, 100% pre-preg construction that premium European carbon manufacturers such as Ilmberger built their reputation on — Bestem uses that same technology and adds a superior UV-resistant coating on top of it.
Will it fit my RS 660 or Tuono 660?
The Aprilia RS 660 carbon fiber sprocket cover (SKU CBAP-RS660-SPC-T) fits:
- Aprilia RS 660 — 2021, 2022, 2023
- Aprilia Tuono 660 — 2021, 2022, 2023
It is a twill-weave part that reuses the factory mounting points. The 660 platform's left engine case and sprocket area are shared across the RS and Tuono, which is why one part covers both models.
How hard is the installation?
This is one of the simplest carbon swaps on the bike — a straightforward bolt-on with basic hand tools:
- Remove the fasteners holding the stock plastic cover.
- Lift the plastic cover away from the sprocket area.
- Wipe the chain-lube residue off the case while you have access.
- Set the carbon cover in place and reinstall the hardware, snugging the fasteners evenly.
Most riders finish the job in a few minutes on a paddock stand.
Why buy it from Bestem?
Bestem has been manufacturing carbon fiber since 2005 — more than 20 years — and supplies OEM carbon fiber parts to car and motorcycle manufacturers, so the aftermarket parts are built by the same operation that produces factory-grade carbon. Parts are stocked in Bestem's Atlanta, GA warehouse and shipped daily, worldwide, with live phone support every business day.
FAQ
Does the Bestem sprocket cover fit the Tuono 660?
Yes. The same part fits the Aprilia RS 660 (2021–2023) and the Tuono 660 (2021–2023), because both 660 models share the same front sprocket area and mounting points.
Do carbon fiber parts yellow in the sun?
Standard clear-coated carbon typically begins to amber at around 1,000 hours of UV exposure. Bestem's proprietary UV-resistant coating is rated to roughly 3,000 hours — about 3× longer — and the part carries a lifetime warranty against sun-ray (UV) yellowing.
Is this part pre-preg or wet-lay carbon?
It is 100% pre-preg Toray carbon fiber, autoclave-cured and molded in matched-metal tooling — not wet-lay, hand-laid, or resin-infused. That process delivers consistent thickness, a cleaner weave, and precise mounting-hole placement.
Is a carbon sprocket cover only a cosmetic upgrade?
Primarily, yes — the stock cover is light plastic, so this is about rigidity, fit quality, and long-term appearance rather than meaningful weight savings. The carbon laminate is stiffer than the plastic piece and, with the UV-resistant coating, it keeps its finish far longer in the sun.
Where does Bestem ship from?
All parts are stocked in Bestem's Atlanta, GA warehouse and shipped daily, worldwide. Live phone support is available every business day if you have fitment questions before ordering.