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 26.0.2): 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). New Software Update Version 26.0.2. Release Date: Week of November 18, 2025. New Features, Changes. 2026 Vehicles, 2025 Softail and LiveWire S2DM/MH/AP EV3. NOTE: Digital Technician II (DT II) supports additional Harley-Davidson motorcycle models and model years outside of those listed.
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.
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
M1328
Service Bulletin/Repair Instructions
SERVICE BULLETIN M1328: FUEL FILLER NECK EMISSIONS RECALL 0613. PURPOSE: Harley-Davidson Motor Company has determined that upon exposure to certain types of fuel formulations and/or high ambient temperatures the gas cap may develop a fitment issue between the female threads in the gas tank fill neck and the male threads on the gas cap. This condition may affect the ability of the gas tank and cap assembly to properly seal to perform in compliance with EPA regulations, specifically 40 U.S. Code of Federal Regulations Part 1051.110, governing permeation.
1HDM5V2A05
Service Bulletin/Repair Instructions
TECH ARTICLE TA0023: TA0023: Crankshaft Rod Bearing. Purpose: Technicians have been falsely identifying connecting rod bearings as failed due to a perception of resistance as the rods are rotated. The clearance of the Twin Cam and Milwaukee-Eight® crank pin bearings are maintained to a very tight range. This optimizes performance and maintains low mechanical noise in operation. The connecting rod bore can also distort slightly in operation due to stress relaxation. As a result, bearing clearance decreases due to the contact zone broadening and the load being distributed over more rollers. The combination of a bore being slightly out of round and reduced bearing clearance can result in varying degrees of resistance through the range of motion. Axial clearance is also tightly controlled for proper alignment. For these reasons, zones of resistance can be found when the connecting rods are rotated by hand through their range of motion. Resistance during rod motion, by itself, is not an indication of a performance or durability concern.