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Replace M8 Harley Primary Chaincase Lubricant

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Refill the chaincase compartment with the motorcycle upright on a level surface. M8 models will hold 34 ounces dry and 30 to 32 ounces wet of Harley primary chaincase lubricant. The primary compartment is considered dry if it has been completely disassembled, cleaned, dried, and reassembled. This would only be the case if performing a repair or performance upgrade. Otherwise, during regular service or maintenance, refer to the wet measurements of 30 to 32 ounces.

Correct Harley primary chaincase lubricant level is very important in every compartment or assembly. Under-filling can allow for excessive heat and friction. Overfilling can cause rough clutch engagement, incomplete disengagement, clutch drag, and/or difficulty in finding neutral at engine idle. Excess pressure within the compartment can eventually lead to premature seal or gasket failure.

Pour the specified amount of Harley primary chaincase lubricant through the clutch inspection cover opening. Thoroughly wipe any residual oil from the derby cover mounting surface and the groove in the derby cover. Push a new seal into the derby cover groove by pressing the nubs of the seal into the groove.

Start the derby cover hardware loosely, by hand. Then, tighten the screws in sequence as shown in your factory service manual. The sequence of the five screws is as follows: 12 o’clock, seven o’clock, two o’clock, 10 o’clock, and 4 o’clock. The correct torque spec for these screws is 84 to 108 inch pounds.

The derby cover is a component that will be removed and reinstalled many times throughout the lifespan of most Harley Davidson models. The factory’s torque specs are important guidelines for correctly securing hardware. It is very important that the factory torque specs are always referred to. Notice, we say referred to, not followed. That’s because after the cover has been removed and replaced many times, the case threads may stretch or soften. At this point, tightening the screws to the recommend factory torque spec may strip the hardware allocation(s). Good judgement, feel, and common sense is still essential.

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