Anti drain valve

[Boominginlife]

I'm still in the process of trying to source parts, so it's going to take a while, but there's something that's been bothering me a bit and I need your input. The engine in the Norton Commando 850 has a dry sump, that part I know, but I've seen some scares info that fitting an anti drain valve is recommended. Is this true? I'm asking because I have no knowledge of these engines at all.

 

[Maeo2]

Yeah, you're right to ask, those old dry sump systems can let oil drain into the crankcase over time, some Commando owners do install anti-drain valves, but they can restrict flow. What year's yours?

 

[LieuT]

Why is it that after 50 years of Norton Commando ownership, we're still debating whether anti-drain valves are necessary? If wet sumping's that common, why wasn't a proper fix built into the design ages ago?

 

[Khalid]

Anti drain valves are risky because if that valve ever sticks shut you'll starve the top end, just live with the wet sumping and kick it through before firing.