Yes, replacement CSUs are available for the 2021-2023 SID SL C1.
11.4018.090.025 FORK CSU - DEBONAIR 29 BOOST™ 44 OFF-SET ALUMINUM TAPER BLACK ANO ULTIMATE 80-100MM - SID SL (32MM) C1 (2021-2022)
11.4018.090.026 FORK CSU - DEBONAIR 29 BOOST™ 44 OFF-SET ALUMINUM TAPER DIFFUSION BLACK) SELECT/SELECT+ 80-100MM - SID SL (32MM) C1 (2021-2022)
RockShox service kits and spare parts are best obtained through your local shop or dealer. See our dealer locator, below, to find a dealer near you. If no one is currently listed near you, then please search for local shops via your preferred web browser.
https://www.sram.com/en/dealer-locator
Manuals and additional information about RockShox and SRAM components can be found at our service site, linked below.
https://www.sram.com/en/service
Further questions?
Reach out to Rider Support by Asking A Question at the link below.
https://www.sram.com/en/rockshox/campaigns/rockshox-rider-support