Dave wrote on 09/06/17 at 02:43:26:Look at the right rear cylinder stud, you can see it if you look up the hole in the head beside the carb - the hole goes forward to the opening up by the exhaust port (and the one where the head plug is). The right rear stud can leak oil from the camshaft/rocker area - this stud can be visible where it exits the head casting for a small span. The cure is to remove the head cover, remove the right rear nut and washer, clean the area up and apply sealant to the copper washer and never seize to the nut before you torque it...and you might as well do the left front cylinder stud as well, as those can leak oil as well.
The copper washers are soft when new - but they harden with the operating heat of the engine. They seal well when new - but if they are reused they don't always seal.
The nuts under the intake and exhaust port can leak as well, remove the nuts, clean the area, and apply sealant. These nuts should have a flange machined into them (no flat or lock washer).
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I'll take a close look at that!
I had the impression the leak came from the front right cylinder stud (the one under the plug, and that you can see standing in front, just left of the exhaust).
When you talk about sealant, I suppose the high temp silicone I bought for the cylinder head cover will do?
Thanks for all the explanation!