Mystery Oil Tank

Has anyone seen a tank like this?
It has one pipe on the bottom.

Electra Glide oil tank

Patrick

Electra Glide oil tank

Patrick

Ithought that from the shape but the Glide,at least the 65-86 had just the pipe on the cap neck and the single connection that points to the groove.
I'm thinking this had the twin connection added for a motor that didn't belong to the frame.

Maybe late 70s early 80s California spec when they added breathers/fume collectors at vomitum???

Just been and had a look at my 77 Glide, it's definitely the right shape but mine has only two pipes on the top, one on each "turret".

Clymer gives no clues and I don't have a factory manual for it; it would seem to have the drop-in cartridge oil filter, wasn't that discontinued on later Shovels?

one of the connections appears to have a Brit-style screw-in end. I would guess that it may have been from a Shovelhead modified to bypass the primary cover. I know someone with a bike like that; the bike has a belt primary behind an open-frame cover, but the oil return still has to go to the tank. That bike also has a vent from the tank to divert a limited oil spray onto the rear chain