Ok, this is an interesting thing. 96 FXSTC, riding about an hour few days ago. Upon return, heard hissing from motor. Couldn't find source. Also smelled a distinct oder of sewer/methane gas. The order could've been excess chrome cleaner from earlier cleaning of dragg pipes, however I have never experienced that oder, only amonia type oder. The hissing possible from air escaping from new stainless oil lines recently installed by me about 150 miles ago, however no fluid leak and level good, and dip stick temp gauge 150. As a fairly experienced mech, certified FAA airframes, and all own wrenching for years, I am scratching my head. What would be a easy way of verifying oil pressure/flow? Concern is loss of former and excessive oil temp in cylinders/case.