1935 VLD oil tank question

[Wildcat]

When I took the fuel/oil left side tank off, I see two holes drilled towards the top on the back side.
Are these supposed to be there?
Thank you

[Steve Slocombe]

Yes, those are witness holes to see if either of the oil or fuel tanks are leaking. There is a double-skinned divider between the two tanks, with the holes over the gap between the two sides.

[Wildcat]

How does that work?
Thank you.

[Steve Slocombe]

Dear Wildcat, if the oil tank is leaking into the double wall divider then oil comes out of the holes. If the fuel tank is leaking into the divider then fuel comes out of the holes. If you've ever seen one of these tanks apart you'll see it is a complicated construction. As mentioned earlier, there is a double walled divider, but in addition this wall is pierced by the hand oil pump tube at an angle, so you have brass collars at each side of the dividers soldered onto the brass hand pump tube and divider. In practice, the Harley guys knew what they were doing so this is a pretty robust construction, and all soldered of course. Usually the left tanks hold up after all these years, as the front part is protected by the oil and the rear reserve section is not filled and emptied as much as the main right tank, so does not get the pitting at the bottom from water coming out of the fuel.

[sswaney]

IMG_0718.JPG
I thought I had a picture of just the bulkhead but couldn't find it.
Here is one during assembly. Kind of gives you the idea of how it works.
top of tank is down in the picture

[Wildcat]

Thank you very much
very interesting