Had my hands in a couple of motors last week. An early XS1 that, judging from the bearing seats, has had as hard a life as Keith Richards face. An XS-D that looks pretty clean inside. Both had what look like original filters.

Top: XS-D .. Bottom: XS1 – both showed damage from over-tightening the screws.

Neither gasket had been pre-treated before installation. An SF hammer was required. The gaskets did separate. In half.

Early filter left with full metal jacket. Right: pleated mesh with magnet, right-hand end slightly crushed. Mesh on both sides intact.

Rear: Early filter has no magnets. Mesh is only spot-welded. Later filter has magnets both sides. Mesh is fully cemented. Much more surface area. Mesh is finer.

Early oil flow problems? Filtration issues? Strange the prone corner was never properly reinforced.

Left ends intact.

Fronts. XS1 filter, mesh has started to separate at the spot-welds.

Although I’ve seen much worse both these motors could have benefited from a few more oil changes.

Was pleasantly surprised to see the original XS1 filter here. And that it had survived so much punishment for so long before giving out.

Both engines have obviously been warmed up slowly-the ends are still intact. The mesh separation on the early filter probably derives from crankshaft rotation – from the look of the bearing seats this motor has sung – full throat – louder than Sleazy Joe.
(143.2dB in Hassleholm, Sweden, 2008)

The XS-D filter could make a good emergency reserve. After fitting an end protector. And rechecking each oil change.

Take care of your engines and they will take care of you. These are very much ladies.