How to Change the Oil on a Harley Davidson Twin Cam Engine

• Empty the engine oil tank and fill it with fresh oil. The engine oil capacity is about 3 quarts (2800 ml).
• Drain the transmission and refill it with fresh fluid. The transmission holds 24 ounces (710 ml).
• Drain the primary chain case and fill it with oil until it reaches the bottom of the clutch hub. This takes about 1 quart (950 ml) of oil.

Take your bike for a ride. The oil needs to be hot and thinned out before you can drain it.

Learn where to drain the oil. There are three places you need to drain your oil from: the engine, transmission, and primary chaincase. The drain plug on all three of these pans requires a 5/8" socket or 1/4" Allen wrench to remove.

Remove the oil fill cap. This will allow your old oil to flow out of the bike faster.

Drain the engine oil. This is easiest to get to from right side of the bike. You will need to use your 5/8" socket.

Remove the transmission oil fill plug. You will need to use a 3/8" Allen wrench.

Drain the transmission oil. The transmission drain plug it centered directly above the shock absorbers. Because both the engine and transmission drain plugs are so close to each other, they can easily be drained simultaneously into the same drain pan.

Stand your Harley upright. Now that your engine and transmission oil are draining, stand your bike upright until oil stops running out of the holes. This is important to get as much old oil out of the bike a possible.

Inspect the drain plugs. There are magnets embedded in the end of each drain plug. These magnets collect any metal shavings produced from normal wear in the engine and transmission. Furthermore, inspect the rubber o-rings on the plug. If they are worn, they must be replaced.

Re-install the engine and transmission oil drain plugs. You may want to use a torque wrench to tighten the plugs 14 to 21 feet (4.3 to 6.4 m)-lb; otherwise, tighten until the plugs are fully seated and not stripped.

Remove the oil filter. Place your drain pan under the front end of the engine. While removing the oil filter, use the oil filter drain funnel to make sure you don't make an oily mess on the bike or the floor. Alternatively, you can shove a rag under the oil filter prevent a mess. Have several rags on hand because this can get very messy.

Install the new oil filter. When installing a new oil filter you must always lube the new oil filter gasket with a little bit of motor oil. Screw the filter on until the gasket makes contact with the oil filter housing, then turn it another 3/4 or a turn. This must always be done by hand. Never use a wrench to tighten an oil filter.

Drain the primary chain case. This is the beginning of the final leg of your oil change. Find the drain plug in the bottom side of the chain case. Place your drain pan under the plug. You will need to use a T-30 to turn the plug out. The picture of the plug's location is in next step.

Remove the derby cover. While the chain case is draining, remove the derby cover. The five bolts on the derby cover are removed using a T-27.

Inspect the derby cover gasket. If it is in good shape, don't bother replacing it.

Fill the primary chain-case with oil. This is best done by using a primary chain-case funnel. Fill until oil reaches the bottom of the clutch hub. This should take 1 quart (950 ml; 33 imp fl oz). In the photos, a chain-case funnel was not available, so it was fashioned out of a scrap piece of plastic.

Re-install the derby cover. When you do this, make sure to use a torque wrench. Those bolts are extremely easy to over-tighten and strip the threads. When torquing, make sure to tighten in a star pattern.

Fill the engine oil tank. The engine oil capacity is 3 quarts (2,800 ml; 100 imp fl oz). Most likely there is still oil left over in the sump, so fill it with 2 quarts (1,900 ml; 67 imp fl oz) and check the dip stick. Add oil until the oil level is between the low and high indicators on the dip stick. Replace the fill cap.

Fill the transmission. The transmission holds 24 ounces (710 ml).

Take your bike for a ride. Once it is at an operating temperature, check for any leaks.