I just completed (so I thought) a rear main seal replacement / oil pump seal replacement on my R100S engine. The new seal began leaking within a 100 miles. Pulled the flywheel back off yesterday and carefully cleaned / dressed the mating surface on the flywheel. The surface had a little discoloration prior to cleaning it up with crocus cloth. The flywheel surface looks good, no wear or grooves visible to the eye. Put it back together this AM and again am beginning to lose oil from behind the transmission. The old original seal was loose in the bore and I was able to pull it out with my fingers. The new seal went in nice and snug. ....I have an aluminum disc that fit the seal outside diameter and was able to "tap" the new seal in without any trouble. The seal looked straight and was not messed up on installation. One thing I noticed, the seal lip on the "new" seal is a very hard material and not soft like most seals I've seen. Is that normal?....or did I get a 40 year old "new" seal? I'm running out of ideas on what in the world is wrong...or what I'm doing wrong.... Any inmate insight and opinions would be appreciated. I just ordered another new seal and I'll be able to remove the transmission blindfolded with all this practice. Bike is hooked to a sidecar so that makes it even more fun to remove.