Technical service bulletins are instructions a manufacturer sent its dealers about a known fault. They are not recalls and the work is usually not free, but they are the clearest signal of a problem the manufacturer already knows about.
M1679
Service Bulletin/Repair Instructions
SERVICE BULLETIN M1679: AFTERMARKET EXHAUST HEADER DEBRIS. PURPOSE: Initial release. This bulletin informs dealers that Harley-Davidson has identified instances of premature engine failure due to abrasive particle wear, specifically from debris inside new aftermarket exhaust headers. Recent evaluations have identified that certain newly manufactured exhaust headers may contain residual hard particles that, if not removed prior to installation, can migrate through the engine system and cause accelerated component wear or severe mechanical damage.
M1490
Service Bulletin/Repair Instructions
SERVICE BULLETIN M1490 (V 26.4.3): DIGITAL TECHNICIAN II - UPDATES AND RELEASE NOTES. PURPOSE: Revision. This bulletin informs dealers that Harley-Davidson has made a software update to Digital Technician II (DT II). DIGITAL TECHNICIAN II (PART NUMBER: HD-48650). Version 26.4.3 Release Date: Week of February 25, 2026. NOTE: Software version (26.4.3) will need to be manually installed only if current software version of DT II is (26.0.2). Refer to bulletin M1713 for instructions. New Features: Support for 2026 LiveWire Vehicles, LiveWire S2 Vehicle Status: Display notification when vehicle has unconfigured Electro Hydraulic Control Unit (EHCU) module, Vehicle Setup: New operation to support Anti-lock Braking System (ABS) / EHCU Correction, Reflash: Enabled EHCU calibrations for vehicles previously ineligible for update, requiring ABS / EHCU Correction to be performed. 2021–2025 Pan America (RA1250), Pan America S (RA1250S), Pan America ST (RA1250ST), CVO Pan America (RA1250SE): Reflash – Updated Electronic Control Module (ECM) software calibration to improve quick shifter performance. Changes: Infotainment Control Unit (IFCU) Customization – Correct issue where speakers were improperly configured.
M1705_Dealer Letter
Service Bulletin/Repair Instructions
SERVICE BULLETIN M1705: X350RA RETAIL CONVERSION KIT (DEALER COMMUNICATION LETTER). Guidelines: • Vehicles must be more than 2 years from SWR date in Riding Academy fleet service, and the manufacturer's warranty expired. • Retrofits that are defined in Service Bulletin M1705, X350RA Retail Conversion Kit MUST be completed prior to vehicle resale. • An updated refleet policy can be found in the H-D Riding Academy New Rider Course Operator’s Manual (exhibit A of your Operators Agreement, found on H-Dnet).
M1705
Service Bulletin/Repair Instructions
SERVICE BULLETIN M1705: X350RA RETAIL CONVERSION KIT. This bulletin informs dealers the availability of a Rider Academy Parts and Accessories (P&A) Conversion Kit (Part No. 91800090). This kit allows dealers to convert the Riding Academy Harley-Davidson X350RA vehicles for customer retail sale. Refer to Isheet 94100747 which is an Attachment to this bulletin in Service Information Portal (SIP).
W146
Warranty Program/Extension
WARRANTY BULLETIN W146 (REV C): TIRE TREAD DEPTH GUIDE-UPDATE. PURPOSE: [Revision C. Updated: Tire Tread Depth Guide. Add tire part numbers 43100063, 43200035,43100029A, 43100033A and 43200045A.] To provide tire tread depth specifications for the dealership network to consult when filling warranty claims on used tires. Please see the Warranty Manual of your region for tire policy guidelines.
M1664
Service Bulletin/Repair Instructions
SERVICE BULLETIN M1664: X 350, X350 RA AND X500 - DIAGNOSTIC CODES AND ABS SERVICING. PURPOSE: This bulletin advises dealer technicians on the correct procedure to access diagnostic trouble codes from the Electronic Control Module (ECM) and when performing Anti-lock Braking System (ABS) service. This procedure is not currently in the service manual but will be updated in the future. NOTE: The X Series of vehicles does not use Harley-Davidson Digital Technician II (DT II).