When To Switch To Synthetic Oil In Harley-Davidson Milwaukee-Eight Engine?

A reader asks: I have a 2017 Harley-Davidson Street Glide Special with the new 107 Milwaukee-Eight engine. When is it safe to switch to AMSOIL synthetic oil in this engine? How often should I change the oil after the break-in period?

Our answer: Harley-Davidson suggests changing the oil in Milwaukee-Eight engine after the first 1000 miles from new and then every 5000 miles thereafter. But when should one change to a synthetic oil for the first time? We submit that you can safely switch to synthetic after the 1000-mile break-in period. The piston rings will seat properly and there will be no oil consumption issues going forward. Some customers will do two short intervals of approximately 750 miles with conventional oil. Then they will permanently switch to synthetic oil.

Related: Compilation Of Harley-Davidson/Synthetic Oil Articles 

Once the engine is broken-in, you can safely double Harley’s 5000-mile oil change recommendation with AMSOIL Synthetic 20W-50 V-Twin Motorcycle Oil. AMSOIL’s EAOM-134C oil filter is also designed to match the Synthetic V-Twin 20W-50’s long service interval capabilities.

20W-50 V-Twin Motorcycle Oil offers unparalleled performance and wear control for your Milwaukee-Eight motor. It can also be used with confidence in the primary chaincase and transmission. If you prefer dedicated fluids for the primary and transmission, check out AMSOIL Synthetic V-Twin Primary Oil and AMSOIL  Synthetic V-Twin Transmission Oil. Regardless of which AMSOIL option you choose, expect cool, smooth operation and optimized shifting.

The AMSOIL EAOM134C oil filter features stout construction and world-class wear particle removal. The long mileage capability and superb engine protection makes this unit a great value for the new Harley Milwaukee-Eight engine.

One of the most convenient aspects of the AMSOIL V-Twin Oils and Oil Filters is that they are ideal for low- and high-mileage Harley owners. Low-mileage riders can easily go the season on one oil change. Ultra-high-mileage riders don’t have to stress about the need to change oil partway through long trips.

Regardless of the oil change interval you settle upon, we recommend changing all fluids in the Milwaukee-Eight engine before winter storage.