Sump plug washer / seal

Ever since buying the bike I have had a slight but persistent oil weep from the sump plug. About one drip every two or three days.

Tightening didn't help so I took it out and saw that no washer or O ring was fitted. I suspect this was the issue but thought I would check here to see if it is meant to have one or not. Can anybody remember? I'm sure that I can find a rubber O ring to fit but I'm not sure about heat resistance?

Incidently a lot of oil came out for a supposedly dry sump motor. My pyrex jelly dish was only just big enough!

Appreciate a heads up on the seal if anybody here knows.

Thanks

Yep, copper washer.

Previous owner of my bike didn't have the washer in there either don't know if it was leaking or not though cos I changed the oil as soon as I got it. The bolt was done up super tight which is some scary shit when you can see there's no washer in there and you don't know if they've over tightened it and damaged the thread!

Turned out was ok, I just got some aluminium washers from the local automotive store as it was a Sunday and the bike shops were closed.

Thanks guys, really helpful.

Will grab a washer and crack on.

Mine was also done up tight and i tightened it a bit more but thread seems ok thankfully.