K-Tech Fork Oil Seal & Dust Cap Kit – Aprilia RSV4 / 1100 Factory / R / RR / RF (2009–2026) FSK-021

Engineered to the exacting standards that K-Tech's suspension programmes demand, this fork oil seal and dust cap kit delivers a precision-fit, long-service replacement for the Aprilia RSV4 family. The seals are manufactured by NOK — the globally recognised Japanese specialist whose oil seal technology is trusted by every major OEM — ensuring the same standard of sealing integrity you would expect from the factory, with the added reassurance of a part sourced specifically for this application.

Key Features

• NOK-manufactured oil seals: industry benchmark for fork seal quality, durability and consistent performance across temperature ranges
• Precision inner diameter of 43.00 mm and outer diameter of 55.00 mm for a correct, leak-free press fit
• Dust caps included to shield the fork internals from road grit, moisture and debris — extending service intervals
• Direct OEM replacement: no modification required, fits the RSV4 and Tuono fork legs straight from the box
• Complete kit — two oil seals and two dust caps — covering both fork legs in a single purchase
• Part number FSK-021 for unambiguous cross-referencing and warranty traceability

Heritage, Finish and Design

K-Tech Suspension has built its reputation across World Superbike and British Superbike paddocks on the principle that every component in the fork assembly matters. The FSK-021 kit reflects that philosophy: NOK's seal compound is chosen not simply because it meets minimum specifications, but because decades of OEM supply to Japanese manufacturers have proven its resistance to oil degradation and its ability to maintain a consistent wipe across a hard-anodised fork leg. The dust caps are profiled to sit flush with the fork leg surface, preserving the clean aesthetic of the RSV4's front end whilst performing the unglamorous but essential job of keeping contamination away from the seal lip.

Performance and Reliability

A weeping fork seal is more than a cosmetic problem — oil migration onto the brake disc is a safety-critical failure on a machine as capable as the RSV4. The NOK seal used in this kit uses a precision-ground lip geometry that maintains contact pressure against the fork stanchion throughout the full range of suspension travel, whether the bike is being ridden on a fast road or pressed hard through the braking zones at a circuit. Pairing the oil seal with the matching dust cap is the correct approach: the dust cap acts as the first line of defence, and reducing contamination at that stage directly extends the working life of the seal behind it.

Fitment & Compatibility

This kit fits the following Aprilia models:

• Aprilia RSV4 (2009–2026)
• Aprilia RSV4 R (2009–2026)
• Aprilia RSV4 RR (2009–2026)
• Aprilia RSV4 RF (2009–2026)
• Aprilia RSV4 1100 (2019–2026)
• Aprilia RSV4 1100 Factory (2019–2026)

Installation should be carried out by an authorised K-Tech Service Centre using the correct fork seal driver and associated tooling. Improper installation can damage the seal lip and compromise fork performance and safety.

Specifications

• Part number: FSK-021
• Inner diameter: 43.00 mm
• Outer diameter: 55.00 mm
• Seal manufacturer: NOK
• Kit contents: 2x oil seals, 2x dust caps
• Application: front fork oil seals and dust caps
• Fitment: Aprilia RSV4 / 1100 Factory / R / RR / RF (2009–2026)