Ironhead Sportster Fluids and Battery Service

Kevin Baas from Vintage Bike Addiction and Baas Metal Craft is back with us again. This time, Kevin is preparing to walk us through a thorough service on this 1977 Ironhead Sportster.

This Ironhead Sportster is actually decades newer than what we typically see Kevin standing next to. It is much more likely to catch Kevin wrenching on a Knuckle or Panhead Harley-Davidson. Kevin will be addressing every service point of this Ironhead Sportster. This will include all fluids, all adjustments, and more.

Kevin has already started the Ironhead Sportster and brought it up to operating temperature. This is important to do prior to pulling any drain plugs. The oil will drain out better, flushing more contaminants along with it. Older Harley-Davidsons are also known to sump. This means that over time, motor oil from the oil tank can slowly sump into the crankcase below. Running the motorcycle will cycle the oil out of the crankcase and back into the oil tank.

Also, if oil was drained and replenished without scavenging oil from the crankcase first, the oil system can be easily overfilled. Kevin uses a ⁵⁄₈” socket to crack loose the oil tank drain plug. A funnel is used to help direct the drain oil away from the motorcycle.

It is important to examine the magnetic drain plug as well as the drain oil. If any large shards or chunks of metal are present, a closer examination of the motorcycle may be necessary.

The oil fill cap/dipstick is removed along with the drop-in filter canister. The old filter is removed from the canister and discarded. Kevin cleans the canister housing and installs a new oil filter. Next, Kevin moves to the left side of the motorcycle. He uses a ³⁄₄” socket to remove the drain plug for the primary and transmission cavities. Again, he closely examines the used oil as it exits the case.

Kevin checks all electrical functions prior to the removal of the battery. He visibly inspects circuit breakers and wiring beneath the seat.

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