How to check PCV and Delay valve?

I’m about to overhaul the entire braking system of my VFR.
How do I check if the Proportional Control Valve and the Delay Valve of the brake system is working properly?
The Hayness manual says that these parts cannot be overhauled. But should be replaced if they’re not working. But it doesn’t t say how to check their function…
Of cause I could just replace them with new ones, they only cost 500€ for the PCV and 200€ for the DV

 

If you download the service manual for the VFR, there is a full section (at the end of the manual, technical features) on how the different components of the LBS are meant to work. After I delinked my last VFR I had the old components laying around so I diassembled the PCV just to see what was inside. The disassembly was easy enough as it was just held together with screws and then a circlip inside. There was nothing inside that could not be cleaned and reassembled, just a couple of o-rings. I did not do the same with the DV.

 

If only there some kind of control, like a pedal, near the right articulating ankle of the body that could be activated, or depressed, to engage the rear brake when needed or wanted.

 

Ohh, I see, there a lot of nice info in the "technical features" section. Hmm... it seems strange that they dont make a o-ring/rubber service kit for this. It looks to be much simpler to service this than eg. a front fork.

 

There's quite a few bis of the VFR that are considered "unserviceable" including the LBS parts, but you can add the fork dampers and the SMC filter cartridge to that, and I'm sure there are other parts too. Given the service conditions I doubt the o-rings would ever need to be replaces in the PCV spool but if you have to, just find a local industrial seal supplier and take in the old part.