Can anyone tell me what this thing is that is hanging underneath my 92 FLHS? It does not appear in my manual, does not appear anywhere that I can find in the online microfiche drawings. It appears to be connected via the hose on top to a 90 deg. fitting coming out of the side of the crankcase. The hose coming out of the bottom of this thing may or may not have been the source for a small (maybe 2 in. diameter) spot of moisture on my garage floor.

Could it in any way be related to the fact that my machine was running fine on Sunday, but on Tuesday it was rough starting and the engine ran very roughly?

 

Looks like someone may have added a crankcase breather valve. It didn't come from the factory like that.

 

it looks like a "pre-filter",their used on drag bikes or customs as a oil filter on the feed line.putting it on the breather wont hurt or help anything.if it is a one way valve,like a PCV valve (some guys will put them on the breather line) it wont hurt anything either

 

, and it looks like a filter on the outside surface which is plugged up and needs to be changed.

 

yes,if it is plugged on the end,it needs to be unplugged (looks like its just a piece of hose on the end,but if it is a plug,unplug it)

 

I have a filter similar to that on my sig bike without a hose on the end of it, but the filter has an inlet ONLY. So, I`m going to assume that it`s crankcase breather, and that the filter keeps out dirt from the road without oil leaking from it.

 

Maybe a Hayden Crank Vent?

 

I'd suspect that is it, or a rendition of that.
Glorified nothingness.
Scott