Exhaust bypass valve question

I tested mine with a power bleeder. You know, the units you can use to pull brake fluid & clutch fluid through your system without pumping the pedal.

I just hooked the suction end up to the bypass valve and pulled the trigger. The vacuum was applied and the valve went open.

 

If you discover that it is not working, here is a good tshoot flowchart:
http://www.ferrarichat.com/forum/140648021-post15.html

Diagram of the operation is here, post #10:
http://www.ferrarichat.com/forum/348-355-sponsored-bradan/340885-pass-valve-operating-details-355-5-2-a.html

 

Not very scientific I know, but mine (and a used replacement bought as a spare) open quite a bit by just sucking on a length of tube connected to the valve - i.e. not a lot of vacuum is required to tell if it's working to some extent. This can be done in situ.

 

I had mine tested by having my son rev the engine to around 5000 RPM and looking at the bypass valve opening by seeing the stem of the valve moving up and down

 

You should be able to just manually move the pushrod by hand and could wire it open if you want to.