Classic Motorcycle Build

Remove and Install Primary Cover Harley Twin-Cam

Article by Mark Trotta

Reasons for removing the primary cover include replacing the clutch or stator and adjusting or replacing the primary chain.

remove outer primary cover on Harley Davidson motorcycle

Or maybe your wife is complaining about those oil spots on the driveway.

leaking primary cover Harley Davidson motorcycle

Here's a step-by-step guide on how to remove and install the outer primary cover on 1999 through 2006 Harley Touring models. Newer models 2007 and up have an automatic chain tensioner, so procedures are slightly different.

Dyna and Softail models are basically the same as Touring models, but have different covers and gaskets.

Torque specs are listed at the end of the article.

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Tools Needed

Along with basic hand tools (wrenches and sockets), you'll need T27 and T30 Torx bits.

Harley Twin Cam Remove Outer Chaincase

Getting Started

To avoid spilling oil on the concrete driveway, I placed a 3' x 4' metal drip tray underneath the bike.

Road King outer primary cover removal

On Touring models, you need to remove the left footboard (socket screw with lock washer).

Harley Road King floorboard removal

You'll probably need to unbolt the left rear foot-peg as well.

Twin Cam primary fluid drain and refill

NOTE: Some models may also have an exhaust pipe or heat shields in the way.

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Drain The Fluid

Removing the derby cover allows the oil to drain quicker (5 bolts, T27 Torx).

Place an oil pan underneath the primary. A T30 Torx bit removes the drain plug.

Harley Twin Cam 3 hole oil change

Read: DIY 3 Hole Oil Change

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Two Different Bolt Lengths

There are 10 primary cover bolts which are removed with a T27 Torx bit. The bolts are two different lengths; five are short (1-1/4") and five are long (1-1/2").

To keep them in the correct order, either draw it out on a piece of paper, or punch holes in the shape of the cover in a piece of cardboard. This will save you time on reassembly.

Do I Have To Remove The Inspection Cover?

On 1999-2006 Twin-Cam engines, removing the inspection cover is optional (4 bolts T27 Torx).

motorcycle service and maintenance

On Evo Big-Twins, two of the four inspection cover bolts go into the inner primary cover, so it must be taken off.

Stuck Cover

Once all 10 bolts are out, and the cover doesn't come off, try tapping it with a rubber mallet to break it loose.

primary chaincase removal Harley twin-cam engine

You can also try to break the seal with a thin flat-blade screwdriver, but if you do, go up from the bottom in case it leaves a small mark.

Remove Outer Primary Cover on Harley Davidson motorcycle

When the cover is loose, carefully pull it outward and downward to remove it.

Remove Outer Primary Cover on Harley Davidson motorcycle

Outer primary cover 1999-2006 Harley Touring models 60665-99

NOTE: If your cover is brushed aluminum, you may want to polish it before putting it back on.

Read: How To Polish Aluminum Engine Parts

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Gasket Replacement

For all of my Harley motorcycle projects (Big Twins, Ironheads, Flatheads), I prefer James Gaskets.

James Gasket 34901-05-K for Harley Twin Cam

Best gaskets on the market. Made in USA.

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Shop: James Gasket Primary Cover Gasket Kit

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Reinstall Cover

Clean gasket surface and align new gasket on dowels. The gasket is awkward to hold in place, and the factory service manual advises against using sealant.

Once the new gasket is on, hand-start all 10 bolts but don't tighten yet.

Make sure the gasket is properly seated all the way around.

Install Outer Primary Chaincase on Harley Big Twin engine

I took a few pictures from underneath to check that all the bolts went through the holes in the gasket.

Once everything looked Ok, I snugged all the bolts evenly, then torqued them to 100 Inch/Pounds.

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Derby Cover and Gasket

The Motor Company calls it a clutch inspection cover, but it's commonly referred to as a derby cover.

twin cam primary fluid drain and refill

Inspect the derby cover gasket. Clean or replace as needed.

Harley derby cover gasket 25416-99c

New James Gasket on left, old H-D gasket on right.

Tightening sequence for cover, with #1 on top, going clockwise is 1, 3, 5, 2, 4.

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Torque Specs

Primary chaincase bolts torque to 84-108 Inch/Pounds.

Clutch inspection bolts torque to 84-108 Inch/Pounds.

Chain inspection cover bolts torque to 84-108 Inch/Pounds.

Chaincase drain plug torques to 36-60 Inch/Pounds.

torque specs for Harley Twin Cam engine

Having an 1/4" drive inch-pounds torque wrench is highly recommended.

Install Outer Primary Cover Harley Davidson motorcycle

When done, start the bike and let the engine idle for a minute or two. Check underneath for leaks.

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Notes and Misc

After removing the chain inspection cover on my 2005 Road King, I found that the primary chain needed tightening.

Twin Cam primary chain inspection cover removal

It was difficult to move the adjuster shoe accurately through the 4" x 4" slot, so I took the chaincase cover off for easier access (it was worth it).

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Articles of Interest:

2005 Harley Road King Review by Owner
Road King Handlebar Adjustment
AGM Motorcycle Battery Review
Motorcycle Gear For Senior Riders
Twin Cam Road King
Sunday Morning Motorcycle Ride