Well bet you were all thinking this was dead and gone.
So after removing my OEM V/V with Griso spring to try to lower the presssure a little I then couldn't get the valve to seal well again.
I purchased an HMB valve and tried that but although I did get static tests that looked great whenever I put it in the engine I just never got the pressure I was expecting. The only explanation I can think of for differences I experienced between static and engine testing, is that oil pressure in the bike is constantly fluctuating probably at quite a high frequency so the valve is constantly chattering and you can't replicate in a static test.
Anyway I took the PRV out of the 1100 Sport which is identical apart from the spring and used it with the Griso spring in. Static tests with the 3mm spacer showed the valve lifting at 120psi, a tad too high for my liking so I removed the spacer and got the v/v lifitng at 85psi.
Put that in the HiCam engine and did a crank run, 68psi.................Hmmm
Today I ran the engine, cold oil idle was around 80 psi and when the oil got hot 60-80 C the valve seemed to be controlling at 68psi.
Before I had 83psi setpoint and the valve controlled throughout the range, but I think because now with the lower setting of 68psi, what's happening is the valve lifts earlier and the system pressure vs the PRV lift pressure is a larger delta. So when the oil is cold the valve gets choked and system pressure rises above the valve setpoint.
I'd ideally liked to have the lift pressure to be a bit higher but learning from my previous experience I'll leave it at 68psi and call it "job done"
Even at this lower pressure setting it's night and day over the standard spring with its 55psi cold idle and lower operating pressure throughout the range.
Finally it looks like I've arrived at, if not the ideal solution, pressures that seem reasonable.
The next question is how will this affect cooling? I'm hoping the higher system pressure will lead to the engine possibly ruunning a bit cooler, but that's for the summer and a good run out.................and that's a bit away yet