Check a VIN

March 14, 2026 Service bulletin

Aftermarket exhaust header debris. purpose

Harley-Davidson technical service bulletin M1679 for 2016-2019 Harley-Davidson Flhtcu, 2016-2026 Harley-Davidson FLHX and 2016-2024 Harley-Davidson Flhtk and others.

Bulletin number
M1679
Component
Engine
Summary
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.

Owners of these vehicles have filed 120 complaints in the engine category.

Vehicles covered

VIN decoder

See the problems and recalls for an exact car

Buying a used Harley-Davidson Flhtcu?

Check the exact car before you pay: accidents, salvage or flood titles, odometer readings and previous owners.

Check its history