I decided to change the oil in my 83 XR 1000 I have worked on all kinds of engines all my life, but when it comes to a harley, I dont know what Im doing. I drained the oil tank and then removed the drain plug under the left rear case. I got very little oil out of the case. My question is, do I have to refill the crank or will it refill from the system. I know that there is an oil level screw on the left side under tha shifter. When I removed it after I refilled my oil tank and ran the bike for a few minutes, I noticed the lack of oil there. How do I refill the case and how much do I use. (untill it flows out the inspection plug.)