I restored the engine of a matchless G3L. the engine runs well but after 5 minutes from its ignition the oil flow in the tank decreases causing it to stop. while it is running it can be seen that smoke comes out of the cylinder head because it is wet with oil.
All seals are new.
The screw to adjust the oil flow on the motor head is unscrewed more than three turns.
what's the problem?
I think that screw in the cylinder head should be half turn out, also check that the oil ways in the rocker shafts are clear.
when I fit the rocker gasket I normally smear a bit of sealer first