Change Oil and Filter in Harley Davidson Sportster With an Evolution Engine

If you have owned a metric motorcycle and have done oil and filter changes on it yourself, but now have acquired a Sportster and want to do the same thing, you will likely be surprised a by a few quirks Harley Davidson Sportster has in this respect. The Sportster engine has a dry sump oil pump design, which means that all of the oil is contained in an oil reservoir (a.k.a. oil bag) on the side of the bike and is continuously circulated from the oil bag through the engine and back into the oil bag. The oil bag is connected to the oil pump via hoses instead of the pump sitting in the sump and pumping oil as in most cars and wet sump bikes. This is a major difference in the engine oil circulation system of the Sportster. The primary chain reservoir is also a bit different than on most bikes I have seen. It does not have a sight glass and also lacks a special filling hole. When I did my first fluid change I was a bit perplexed about these things, so I decided to create this article to alleviate the discomfort of the potential DIY-er. I want to encourage riders to do their own maintenance because it really gets them close to their machines and makes them more aware of loose fasteners, leaky seals, etc. that may need attention.

Steps

  1. Ride your bike a little to get the oil warmed up. Also, when the bike sits for a few days the oil may drain from the oil bag into the engine. Since this is a dry sump oil system you will be draining the oil bag and whatever ended up in the engine by this type of drain will remain there and will mix with the new oil after the change. Also, the warm oil is much more willing to flow and will drain more readily.
  2. Gather your tools. You will need a drain pan, a flat blade screwdriver, an oil filter wrench, which is optional and I do not use one. Since I am the only one who changes the filter on my bike I know it will not be over-tightened and I will be able to get it off with my hands.
  3. Put the bike on the side stand, place the drain pan under bike close to the rear wheel and find the hose. The free end of it will be plugged with a plastic plug that also doubles as a clip that holds the hose to the frame tube.
  4. Using the flat blade screwdriver unscrew the hose clamp securing the hose plug and move it up the hose past the plug.
  5. After making sure the drain pan is in place to catch the oil, pull the plastic plug from the hose making sure to not get scalded by the hot oil coming out.
  6. Wait until the stream of oil is down to a drip. Straddle the bike and right it. The stream should resume. Keep the bike upright until you hear the stream return to a drip.
  7. Put the bike back on the side stand. You should hear the stream again. Wait until it runs out.
  8. Plug the hose with the plug, but do not tighten the clamp just yet. You'll come back to it after the next few steps.
  9. Move the drain pan under the oil filter and unscrew the filter letting the oil drip into the drain pan.
  10. Wipe the filter seat clean, pour about 4 oz. of fresh oil into the new filter, spread a thin film of the fresh oil onto the filter gasket and screw the new filter on. Tighten it with your hands about a quarter turn past the point of gasket-to-seat contact. Do not over-tighten unless you like using oil filter wrenches. Once the gasket seats the oil will not leak as the oil pressure in these bikes is not high. If you get a leak tighten a bit more, but only a little. I have never had to add torque to my original 1/4 turn.
  11. Move the pan back to the oil bag drain house and open the plug on the house. By this time some more oil has made its way down and you will get some additional oil out. After this re-install the plug, tighten the hose clamp and clip the hose back onto the frame tube.



Tips

  • If you open the oil filler cap after removing the drain plug it will help the oil drain out.
  • People have lots of methods to prevent oil from getting all over the frame and other parts of the bike when changing the filter. I find that the most practical method is to just let the oil drip wherever it may wiping some of the obvious oil drops off with a rag and then washing the bike with a hose paying attention to the places under the filter that got soiled by the oil. This saves lots of time and anxiety about oil draining out. I use the spray-on-spray-off type of detergent and it removes all the oil from the filter area very effectively.

Related Articles