I think TQ has you fixed up here... I just changed the stator on my 98 EVO. It seems to have the same part # on what i looked up. Its an O ring that fits in there. It usually causes your engine oil to leak into your primary... Is that what you got going on?
If it is the mainshaft oil seal you are looking for should be no 4 on the page of the link but at the top of the page you can select other pages this is for 1999 softail Harley-Davidson Parts