I have an ol´ 82 ironhead the 2 plugs that u are talkn about. the top one is a fill plug and the lower one is for your clutch adjustment when you check your fluid there is a screw on the primary fill it with Sport Transfluid , you can get it at a dealer or out of J&P cycles, fill it till it comes out the screw. to drain there is a small plug on the bottom of the primary case. if you have any ?´s email me zrider44@yahoo.com. I suggest ordering a Harley shop manual they cost about 50 dollars out of J&P cycle. they are pretty good bikes but we all want a bigger one. ride hard or stay at home. BILL