Yes, without that O-ring some oil will slip by unfiltered.

Be very careful about which direction you install the filter - installing it backwards blocks the flow and will break the filter cover the first time you rev the engine (and no oil flow can do a lot of damage elsewhere in the engine).

http://suzukisavage.com/cgi-bin/YaBB.pl?num=1099572561

FlyingH wrote on 07/01/19 at 08:29:23:


Dunno.......not sure who made the one you bought.

A used O-ring is better than none at all......and the large O-ring on the cover works for years - I only replace mine when it gets stiff and flattened.