Head Gasket Leak

Hello Z Riders..

I have a 1975 Z1 900 that's freshly built, with APE parts, making it a 1327cc science project. It leaks oil from the outside left rear head bolt, even after using copper/silicone sealant.

Now the head gasket is leaking on the outside left. I tried re-torquing the head all across, to 40 ft/lbs, but it's leaking too much oil to even think about riding.

It was built with the head gasket supplied by APE. Such a drag. The motor is beautifully strong, and I want to ride.

I see myself pulling the head, putting it together with a replacement gasket, but there is no reason to think it won't just leak again. Any thoughts out there..?

Thanks in advance. Mark from Vancouver Canada..

Was the lower head and cylinder top checked carefully for level (dead flat) surfaces?

Were both surfaces sparkling clean?

On mine, there is a "connecting pipe" on each outside edge of the engine conducting oil up from the cylinder to the head and they have two O rings each. Those O rings will leak like a SOB if not replaced.