A persistent leak from the rockerbox/cylinder head joint can be permanently eliminated by
grinding both mating surfaces really flat on a piece of plate glass with fine grinding compound as
used for valves. Oil will leak down the 3/8" cylinder studs and out the head-barrel joint unless the
O-Ring seals under the washers are renewed whenever disturbed. torque
the 3/8" cylinder head
nuts 25 foot-pounds evenly. Pull the 5/16" rockerbox bolts down only until they are firmly tight;
these fine threads strip out of the aluminum head rather easily if forced, but this catastrophe can
be repaired with a Helicoil insert.