Just curious, I'll be changing the fluids for the first time in my FLSTF, before long. I've read that once the oil tank is completely drained and the oil filter is removed, there remains at least 14 to 16 ozs of old oil in the crank. How many of you flush out that oil? Or is it routine to just refill the oil tank and allow the old stuff to mix in with the new oil? If you flush it out, what process do you use? Will appreciate any information on this subject. Thanks.