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August 14, 2026 Service bulletin

Cosmetic cylinder staining (all milwaukee-eight models). purpose

Harley-Davidson technical service bulletin M1733 for 2017-2019 Harley-Davidson Flhtcu, 2017-2023 Harley-Davidson FLHX and 2017-2023 Harley-Davidson Flhtk and others.

Bulletin number
M1733
Component
Engine
Summary
SERVICE BULLETIN M1733: COSMETIC CYLINDER STAINING (ALL MILWAUKEE-EIGHT MODELS). PURPOSE: Initial release. This bulletin informs dealers that cosmetic staining or etching on the inside of the cylinder bore does not have an impact on engine performance, oil consumption, or overall functionality. This bulletin provides example images of cylinders with cosmetic staining, and images of cases where cylinder replacement would be recommended.

Owners of these vehicles have filed 54 complaints in the engine category.

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