01-06-2016, 03:31 AM
As a vintage bike guy, I can attest to the fact that oil will eventually leave a brown film on the inside of the sight glass making it tough to see the oil level. On most vintage bikes, there is a thin aluminum screen of sorts on the back that makes cleaning nearly impossible. It is easy to cut this screen type thing off and wipe the sight glass to clean it. Never could figure out why a screen was placed on the inside as the sight glass is unlikely to come in contact with anything that could touch it.
