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.
M1490
Service Bulletin/Repair Instructions
SERVICE BULLETIN M1490 (V 26.8.3): 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 Version 26.8.3, Release Date: Week of July 24, 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). After (26.4.3) is manually installed, automatic updates will bring DT II to the latest software version. Refer to bulletin M1713 for instructions. New Features - Harley-Davidson: 2023-2024 Touring: Updated Electronic Control Module (ECM) calibration offerings. LiveWire: S2DM/MH/AP: Calibration bundle 10.2.28: Telematic Control Unit (TCU) reflash updates. Change: Vehicle Setup: Body Control Module (BCM) – Tire Pressure Monitoring System (TPMS) Replacement: Correct issue where tire size selections were not available. System Info – Auxiliary Load Controller (ALC): Added Bike configuration field. Data Items – Trike ECM: Improved display of Gear Position when in reverse. Amp – Added support for (Part No. 76001619).
M1727
Service Bulletin/Repair Instructions
SERVICE BULLETIN M1727: BIG TWIN INNER PRIMARY SEAL CHANGES. PURPOSE: Initial release. This bulletin informs dealers of changes to the Inner Primary Seal (Part No. 12052). The seal part number was changed from (Part No. 12052A, black in color) to (Part No. 12052B, brown in color). A new Inner Primary Seal (Part No. 12052C) has been released and the color has been changed back to black.
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.
M1713
Service Bulletin/Repair Instructions
SERVICE BULLETIN M1713 (REV C): DTII UPDATE PROCEDURE FOR SOFTWARE VERSION (26.4.3). PURPOSE: Revision C. This bulletin informs dealers that an issue was discovered in the Digital Technician II (DT II) software version (26.0.2), released on November 18, 2025. The issue prevents automatic software updates to be installed on your DT II computer. A manual installation of the latest DT II software version (26.4.3) will need to be performed if current DT II software version is (26.0.2), to allow future automatic updates. If a manual update to (26.1.5) or (26.3.2) has previously been completed, DT II will automatically update to (26.4.3) and no additional action is needed.. Revision C. Updated: Purpose for Service Bulletin and Required Dealer Action. Updated to Software Version (26.4.3).
M1391A
Service Bulletin/Repair Instructions
SERVICE BULLETIN M1391A (REVU): MIDTRONICS GRX-3110 AND DCA-8000 SOFTWARE. PURPORSE: Revision U. The purpose of this bulletin is to inform the dealer network that a software update to the GRX-3110 and DCA-8000 is now available. DYNAMIC DIAGNOSTIC CHARGER SYSTEM (PART NUMBER: DCA-8000). [Rev U] Added: Description of improvements made to the testing algorithm for GRX software Version P and DCA-8000 software Version E.
PAB1171
Service Bulletin/Repair Instructions
GENUINE MOTOR PARTS AND ACCESSORIES BULLETIN PAB1171 (REV B): SOFTWARE UPDATE FOR SCREAMIN EAGLE PRO STREET TUNER. PURPOSE: Revision B. Updated: Summary. The App has returned to the Apple App Store. This bulletin informs dealers that a recent software update to the Screamin' Eagle Pro Street Tuner application will require the use of a Personal Computer (PC) to complete a Bluetooth Communication Interface (BCI) firmware update.
M1684
Service Bulletin/Repair Instructions
SERVICE BULLETIN M1684: MARKET SPECIFIC BATTERY INTRODUCTION. PURPOSE: Initial Release. This bulletin informs dealers of the availability of new batteries for new Original Equipment (OE) vehicle production and in the Parts and Accessories (P&A) catalog. Availability of the new Absorbed Glass Mat (AGM) batteries will vary by market and will be transitioning over the next few months. NOTE: The ring terminal screws are not compatible between Leoch and East Penn batteries. The new batteries will include new ring terminal screws, which must be used. The ring terminal screws from the old battery need to be discarded.
PAB1165
Service Bulletin/Repair Instructions
GENUINE MOTOR PARTS AND MOTOR ACCESSORIES BULLETIN PAB1165 (REV A): H-D SYN3 SAE 15W50 / SAE 50 AVAILABILITY. PURPOSE: Revision (A) * Updated: Summary, Update table. This bulletin informs of the availability of the SYN3 New Improved Formula, a dual weight SAE 15W50 / SAE 50 Motorcycle Oil. The new formula transitions into inventory as the old SYN3 20W50 product inventory is depleted. Availability varies by SKU and region. The original SYN3 20W50 will be obsoleted when the transition is complete.
M1555
Service Bulletin/Repair Instructions
SERVICE BULLETIN M1555 (REV G): BATTERY WARRANTY GUIDELINES. PURPOSE: [Revision G: Updated: Information on Battery. Update section headers: AGM and Lithium-Ion Batteries.] This bulletin informs the dealership network that Harley-Davidson has provided guidelines for battery warranty.
M1650
Service Bulletin/Repair Instructions
SERVICE BULLETIN M1650: MILWAUKEE EIGHT AND TWIN CAM CAMSHAFT DRIVE GEAR RETENTION KIT CHANGES. PURPOSE: This bulletin informs dealers that changes have been made to the Camshaft Drive Gear Retention Kit and service proceduresfor the Milwaukee-Eight and Twin Cam applications. In an effort to increase the clamp load of the camshaft drive sprocket bolted joint and prevent the drive bolt from loosening in high lift camshaft applications, the following changes have been made: a. The camshaft drive bolt final torque has been increased to 40 ft-lbs (54 N·m) for all Milwaukee-Eight and certain Twin Cams models. See Vehicles Affected. This increase in torque will make the bolt a one time use application. Never re-use a camshaft drive bolt for service after tightening to the increased specification. See service manual for updated procedure. b. A new camshaft drive gear retention kit (Part No. 91800088) has been created. This new kit is compatible with all Milwaukee-Eight and Twin Cam engines using Parts and Accessories (P&A) camshaft and Original Equipment (OE) camshaft applications. See Instruction sheet for specific fitment on Twin Cam OE camshaft applications. The new kit utilizes friction washers to prevent unwanted rotation of components in the drive sprocket bolted joint under stress. The use of liquid threadlocker on the threads of the bolt and pre-lube to the head of the bolt flange and outside of the washer help the bolt reach full stretch when tightening. NOTE: Engines produced at all Harley-Davidson Motor Company (HDMC) plants will not come with the new kits installed. They will continue to be produced with (Part No. 25566-06).
PAB1158
Service Bulletin/Repair Instructions
GENUINE MOTOR PARTS AND MOTOR ACCESSORIES BULLETIN PAB1158: OIL FILTER PACKAGING AND CASE QUANTITY UPDATE. PURPOSE: To inform dealerships that Harley-Davidson has made updates to oil filters including new part numbers, packaging design, and bulk case quantity changes.
M1612
Service Bulletin/Repair Instructions
SERVICE BULLETIN M1612 (REV A): MILWAUKEE-EIGHT AND TWIN CAM TRANSMISSION GEAR PACKS. Purpose: Revision. Update: Notes for Table 3 and 4. * Updated: Part Numbers. This bulletin informs dealers that all: Twin Cam gear packs on CVO, Dyna, Police, Softail, Touring & Trike models and Milwaukee-Eight gear packs on CVO, Police, Softail, Touring & Trike models ordered after December 04, 2023 will not come with the shift drum, forks, shafts and related hardware. Models Affected: 2006-2017 Twin Cams: Dyna models 2007-2016 Twin Cams: CVO, Police, Touring and Trike models 2007-2017 Twin Cams: Softail models 2017-2024 Milwaukee-Eight: CVO, Police, Touring and Trike models 2018-2024 Milwaukee-Eight: Softail models
PAB1146
Service Bulletin/Repair Instructions
GENUINE MOTOR PARTS AND MOTOR ACCESSORIES BULLETIN PAB1146: 68193-95 BULB WEDGE, FENDER TIP LAMP. Purpose: To inform dealers of an issue with the bulb wire terminals not being to specification. The light bulbs were used in numerous front and rear fender tip light assemblies for domestic and international applications.
PAB1084
Service Bulletin/Repair Instructions
GENUINE MOTOR PARTS AND ACCESSORIES BULLETIN PAB1084: SOFTAIL BACKREST PAD IMPROVEMENTS. Purpose: To inform dealers of design improvements for the Compact Passenger Backrest Pads. Some of these pads can become loose resulting in the backrest pad slipping on the sissy bar. The new backrest pads, designated with an ?A? revision, have been redesigned to fix this issue.
1HDY3S9Z01
Service Bulletin/Repair Instructions
SERVICE BULLETIN M1485: 2000 - 2017 SOFTAIL - FUEL TANK GASKET. Purpose: Service fuel tanks for Softail motorcycles are now being updated to include a top plate gasket (Part No. 61381-02A) with all new replacement tanks. Harley-Davidson strongly recommends using the new gasket when servicing the fuel tank. The updated gasket has improved sealing of fuel vapors and improved compatibility with fuel that contains ethanol alcohol additives. Motorcycles Affected: 2000 - 2017 Softails, all models excluding FXSTD, FXSTDSE, FXSTDSE2, FXCW and FXCWC.
1HD-R7V8M-09
Service Bulletin/Repair Instructions
PARTS & ACCESSORIES BULLETIN PAB1067: SCREAMIN? EAGLE SMART TUNE PRO RELEASED FOR SHIPMENT. Purpose is to notify dealers that the Smart Tune PRO ? Automatic Tuning Module is 50-state U.S. EPA approved and released for shipment.
TA0006
Service Bulletin/Repair Instructions
Harley-Davidson is aware of conditions that may result in a streaking appearance or film residue on the inside of some instrument gauges including speedometer and tachometers. This may occur after exposure of the vehicle to humid conditions. This condition may remain even after the moisture has evaporated.