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
M1509
Service Bulletin/Repair Instructions
SERVICE BULLETIN M1509: MILWAUKEE-EIGHT CYLINDER FLANGE NUT USAGE. To Inform dealers of a service manual change. This change affects the flange nut attaching the cylinder/cylinder head assembly to the cylinder stud in all MKE-8 (Milwaukee-Eight®) engines. The flange nut is one-time use and is replaced after removing. An additional change is the lubrication of the flange nut. Verify that only the bottom of the flange nut receives lubrication. Do not allow lubrication on the cylinder stud or on the internal threads of the flange nut. Motorcycles Affected: Vehicles with the MKE-8 engine From 2017 - 2020.
M1492
Service Bulletin/Repair Instructions
SERVICE BULLETIN M1492: 2017 - 2019 TOURING - MILWAUKEE EIGHT - INNER PRIMARY VENT. Purpose: Revision. Harley-Davidson has learned that a small percentage of dealers and customers are finding low transmission oil levels and high primary oil levels during normal maintenance intervals. This could indicate that oil is transferring from the transmission case to the primary housing through the transmission mainshaft. A inner primary vent service kit (Part No. 26500027) is now available to address this issue. The kit allows the primary to breath and prevents excessive pressure. All markets are affected.
1HD-D8A8J-03
Service Bulletin/Repair Instructions
SERVICE BULLETIN M1359: 2014 - 2016 TOURING - HYDRAULIC CLUTCH LINE REPLACEMENT. PURPOSE: REVISION. A leak may occur on some Touring, CVO Touring, Police Touring and Trike models equipped with hydraulic clutch. The leak may occur when the line is replaced or when a P&A clutch line is installed. The area of the leak is at the joint where the clutch line attaches to the secondary clutch actuator (right side of the transmission). Required Dealer Action: Use Snap-on Flare Nut Socket (Part No. GAN85087B) and Snap-on Torque Wrench (Part No. QJR117F or similar) to tighten flare nut. Each time clutch line is installed or torque is adjusted to determine if leak is still present, bleed the clutch system.
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.
1HDT2E2N05
Service Bulletin/Repair Instructions
SERVICE BULLETIN M1463: MILWAUKEE-EIGHT - ROCKER COVER GASKET INVENTORY PURGE AND REPLACE. Purpose: To inform dealers that previous rocker cover gasket design on Milwaukee-Eight? are prone to varying degrees of oil leaks. These leaks may occur on certain vehicles with different combinations of painted, polished and chrome parts. Purge inventory of old gaskets and replace with new gasket which has enhanced sealing features.
M1416
Service Bulletin/Repair Instructions
The purpose of this service bulletin is to communicate updates and corrections to certain 2008-2016 service literature.
1HDC2F9R11
Service Bulletin/Repair Instructions
SERVICE BULLETIN M1456: 2017 - 2018 SOFTAIL - OIL SPINNER RETENTION. This bulletin informs dealers of a production change which addresses oil spinners that could detach from the sprocket retainer on some Softail models with wide primary chaincases. The production change was corrected as of September 13, 2017. Symptom: Unusual clicking sounds coming from primary. Repair only if issue exists, this is not a warrantable claim for retrofit.
1HDG4C4U11
Service Bulletin/Repair Instructions
SERVICE BULLETIN M1450: MILWAUKEE-EIGHT WITH STAGE KITS - LOSS OF POWER OR HIGH ENGINE BRAKING. Revision. Purpose: 2017 and 2018 model motorcycles equipped with a Milwaukee-Eight? engine and a Stage III or Stage IV kit can experience a condition known as sumping during extended periods in low gear, at high rpm or under heavy engine load. This bulletin provides the diagnostic procedure for determining if sumping is occurring.
1HDV7W6E11
Service Bulletin/Repair Instructions
TECH ARTICLE TA0022: Transmission to Primary Oil Transfer. During service intervals, customers or dealers may find oil level in the primary above the clutch cover opening. This also is accompanied by low transmission oil level. 2014 - 2016 Vehicles:For Twin-Cam models, replace the oil seal (Part No. 12068) and sprocket shaft spacer (Part No. 24009-06). 2017 and Later Vehicles: Check the primary and transmission oil levels and adjust the oil volumes as needed. Verify oil levels again in 1,600 km (1,000 mi).
1HDT2L4Q10
Service Bulletin/Repair Instructions
TECH ARTICLE TA0019: TA0019: Oil Spinner Retention. The oil spinner may be partially secured or separated from the sprocket retainer. RESOLUTION: If you determine that an oil spinner has lost retention, inspect the compensator assembly for wear and service as needed. Upon reassembly, replace both the oil spinner and sprocket retainer.
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.
1HD-Q4H7G-02
Service Bulletin/Repair Instructions
Service Bulletin M1430B: BOOM! BOX INFOTAINMENT SYSTEM GENERAL INFORMATION AND SOFTWARE RELEASE 1.20.X DESCRIPTION informs the dealer network that Boom! software version 1.20.3 released December 19, 2016 and is now available to download. This also provides notice that revision 1.20.2 was found to be corrupt. Do not install version 1.20.2 and delete any stored copies.
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.