Mark:
I had the same problem with a '70 Bonnie that leaked (poured out ) of the exhaust tube. The tappet block should fit tightly (forced into the cylinder base). Mine was loose enough to push in by hand. Most likely either the tappet block was worn or the cylinder base was enlarged. After repeated attemps (like you) I used an adhesive called 'YamaBond' and gooped it up making sure not to block the oil feed holes. Sealed her up and stopped the leak!
YamaBond is a grey gasket sealer that is very good that was recomended for the cases.
For the leak on the Primary, all I use is the gasket and coat both sides of it with grease. Makes a good seal too.
Good luck, don't let it get you!
2010 Thunderbird LE 1700 :-)
"We eat, sleep, breath, dream, live, love, and ride motorcycles ..."
