Oil pressure R100gs

[DrFarkoff]

1) go for a ride with the gauge connected,

2) but I’m fairly convinced that it’s electrical. But then!,

1) Take a pillion to watch the gauge!!! LOL

2) It's just a positive feed to the lamp and then to ground through the switch, via a ball bearing in the interior of the switch with a spring pressing it up against a contact which at zero pressure just completes the circuit

Once you start the engine and have pressure the oil pressure pushes the ball bearing off the contact and bingo connection broken and the Oil light goes out

You can do the same thing with a low amp fused wire with a crocodile clip off the positive through a bulb and to the switch

Nominally it will be on and once you start up and have oil pressure the bulb will extinguish

 

[Gelandestrasse]

Heat seems to have something to do with the symptoms. Cold engine - good pressure, hot engine, bad.

My first thought (despite having a pressure gauge I can ride and monitor with if only I fitted it) is the old $2000 o ring issue.

Did OP measure the depth of the oil filter canister and work out how many shims (shims not necessarily needed on this model but depends on canister depth) and if a cover gasket was required?

If yes, then fine, keep fault finding with an oil pressure gauge. If no, or 'I put in everything that came with the kit', then check the canister depth. Pressure drop can occur internally with no leak visible externally.

 

[Blythe59]

Well chaps, quick update, I removed the sump, no pin, the oil was very black though, unusually so as it had covered less than 100 miles! Anyhow, I replaced the oil pressure switch, checked the wiring with a multi meter, all okay, fired her up and went for a ride, no light, yippee.
Only did around 60 miles so this morning I’m heading over the moor to Whitby, back roads to Thornton Dale then over the moor. Fingers crossed.