After installing the O-ring in the head and placing the intake tube just inside the O-ring, I take a tooth pick and place RTV in front of the aluminum washer. Seems to work for a while? Maybe some high temp silicone would be better?

Seems as though the 72 has more trouble with this than the others. But all Saito's I've taken apart back there seem to have nicked O-rings.

Also the O-ring that belongs at the head joint is a harder "Viton" O-ring whereas the one in the carb is a regular O-ring. If you buy a gasket set for a saito, it will have one O-ring in a seperate package inside that says "Viton" on it. The carb O-ring will be loose in the bag.

Enjoy,

Jim