The TC-88, or Twin-Cam 88 cubic inch (c.i.), motor has provided power to most of Harley-Davidson’s motorcycles since 1999. Unlike the “unit-construction” motors used by other motorcycle manufacturers, the TC-88 and the subsequent TC-96 motors consist of three separate components: the motor itself, the transmission unit and an intermediary primary drive system. Each component is lubricated by its own specialized oil, which requires regular replacement to maintain its lubricating properties. Some Harley dealerships insist on changing all these oils at the same time, but the engine oil can be changed on its own.
1. Place the motorcycle on a service stand to hold it in a secure and level position. Unscrew the oil cap from the right side of the motorcycle’s oil tank, which is under the rider’s seat.
2. Find the oil drain bolt on the side of the oil pan under a Dyna or Touring model’s motor. Alternatively, Softail models use an oil drain hose that is located along the left side of the frame, near the transmission unit. Unscrew the drain bolt from the oil pan or drain hose, using a 5/8 inch socket and a socket wrench. Drain the motor’s oil supply into a drain pan.
3. Pull the old rubber O-ring from the drain bolt and replace it with a new O-ring.
4. Screw the oil drain bolt into the oil pan or drain hose until it is lightly seated, using a 5/8 inch socket and a socket wrench. Tighten the drain bolt to 20 foot-pounds using a torque wrench.
5. Unscrew the oil filter from the front of the motor using a cap or strap wrench.
6. Pour a small amount of 20W50 motor oil into the new oil filter until it is filled completely. Coat the filter’s O-ring with oil as well using your finger.
7. Screw the new oil filter onto the motor by hand until it is seated firmly against the motor. Wipe away any spilled oil with a shop towel.
8. Fill the oil tank with up to 2.5 quarts of 20W50 motor oil. Screw the oil cap onto the oil tank.