How Do I Fill the Harley Davidson Primary With Oil?

Primary cover on a Harley-Davidson big twin

Checking and maintaining the proper level of fluids in your Harley-Davidson is important. In addition to the engine and transmission, the primary case requires fluid to lubricate the primary chain and clutch plates.

1. Inspection Cover

   • You check your primary fluid level through the inspection cover, which is the oval cover in the middle of the primary cover. You'll need a T25 Torx wrench to remove the bolts. Have a new inspection cover gasket in case you need it.

   Adding Fluid

   • Add the fluid through the inspection cover. You can use any kind of oil -- petroleum or synthetic -- as long as it does not contain friction modifiers.

   Closing the Inspection Cover

   • Replace the gasket on the inspection cover if needed. Tighten bolts finger tight; then tighten the bolts at 10 foot-pounds. Start with the top bolt and then tighten the bottom bolt. The third bolt is the right one, and the left bolt is last.

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