So this might be a dumb question but what about intalling a shoot-off valve in the oil line to fix wet sumping problem on older Evo motors?

If the problem is that the bottom of the engine gets filled with oil that the check valve in the oil pump lets thru or that by any other reason why not install a shoot-off valve in the oil line before it goes in the oil pump?

I know that there is potentially the risk of someone starting the bike with the oil line off but I'm just asking if it would work or not the valve.

 

Fix problem not symptom...

 

You could also drain the oil and put it back before each ride as well. Both are problematic and are not a real,fix.

 

For a second I thought this was an M8 thread.

 

It is a bad idea, because no matter how careful you are, sooner or later.......

 

Not sure what a "shoot-off valve" is but, if you're referring to a "shut-0ff". You will live to regret it....

 

A shut off valve is OK for the fuel, but not the oil. sooner or later you will forget to open it and then. tap tap tap... Put a new oil pump on it if you can not get the ball to seat good.

 

OR if you are hell-bent to do it...install a valve with a switch that disconnects the starter/ignition when it is closed.

 

That was my thought as well.

The bike already has a valve engineered into the system. If the one on yours isn't working correctly, you're better off solving that problem directly, rather than putting time/effort/money into adding a second valve.

 

OP IIRC the ball in the pump is the same size as your pushrods so go buy 1 pushrod and get some lapping compound and use that to reseat your ball bearing.
Or as mentioned just get a new pump.