Here is the cooler adapter I got off Ebay for the CB750. In addition to an oring, there needs to be a flat rubber or oring seal to go on the engine side of the adapter, to seal against the center protrusion on the engine. a leak here will create an opening between the hot and cold side of the filter. A better system would be to design the filter side of the adapter to look just like the engine....a protrusion for the inner seal of the oil filter to sit up against. Good Luck!!