1988 883 sportster hugger oil draining from oil tank to crankcase after shutdown

No, you're probably draining the small amount of oil that was in the crankcase. All Harley-Davidson engines other than the V-Rod (which I know nothing about) use a "dry sump" oil system. This means that it does not carry it's oil in the crankcase like other motorcycles do. It carries it's oil in a remote oil tank much like a NASCAR racing car. The oil pump pumps oil from the tank to the engine. Once the oil settles to the bottom of the engine, the pump's scavenger stage pumps the oil back to the tank. The oil drain for your Sportster is a piece of hose that plugs onto the frame down low on the left side of the bike back behind the engine. It plugs on just below the pivot for the swing arm. Pull the hose off and the oil will drain.

Good Luck
Steve

Harley has changed the location of the oil drain on Sportsters so many times it's hard to keep up with. Look on the left hand side down low on the frame behind the primary. The hose simply plugs onto a stub on the frame.

Good Luck
Steve

Excess motor oil that blew out the oil cap ,when you've parked for a long time the oil in the tank will drop down in the crankcase,then when you start the motor it will go back in the oil tank and then overflow the oil level...You must have to drain the oil tank again and refill it at the correct oil level....

Look down on the left side of the bike, below the battery and behind the primary. You should see either a plugged hose or a hose that appears to plug onto the frame. This is the oil drain. Remove the plug or take the hose off the stub on the frame and the oil will drain out. Change the filter and refill the tank with three quarts of 20W50 oil.

Ride Safe
Steve

The drain is under the crankcase. Please review the video I'm attaching. Time to wrench.
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Warm up the bike first. On Evolution Sportster's, be sure to change the filter the same time you change oil. The oil may be drained from the tank, by locating a blanked-off hose behind the transmission case, near the frame. Remove the plug and drain into a proper container. One problem with Sportster's (and other HD engines) is that some old oil is always left in the system. You can eject some of this by taking off the plug wires and cranking the engine to expel old oil back into the tank, and hence to drain line. Don't crank the engine more than 30 sec. to avoid damage. Never run engine W/O oil in the system. Recycle old motor oil !!

look on the left side of the bike back underneath the battery. You'll find a large diameter hose back there with either a plug in it or the hose connects to the frame. It will have one of those spring type hose clamps on it. Take this hose off and drain the oil out of the tank.

Umm, did you add oil when it was cold? I would never suggest adding cold. Harleys are a dry sump system and oil can fill the crankcase overnight and give the illusion you are low, thus overfilled when you add and start! heh
The only models not affected by this is oilpan FLH's, all Dyna's, and VRod's. *Any* motorcycle with a oil tank above the crankcase and a pump in between can do this. Just be glad you crankcase doesn't vent to ground, it would have been an even bigger mess. *note* in rare instances this (oil cap popping out) can be caused by excessive crank case pressure IE: cracked ring. cylinder leakdown test would answer this. Doubt an 03 whould have a cracked ring.

Maybe this would help and get the HD factory manual also. http://www.harleydavidsonmaintenance.com/sportster-transmission-oil.html