Does DGR mean Distinguished Gentleman's Ride?
You know, it's funny that you should mention it, but yes, it does!
be careful and not get an old Triumph PRV, because it does not become activated until 75 PSI, BSA is less PSI
one of the guys here on the forum said you have to modify the washers or something on the Triumph PRV to lower the kick in pressure so it works for the BSA, ask Musky, he should have run into this problem. Might try search in forum. If memory serves BSA is supposed to allow oil to cam tray at about 50 psi, NOT LATE AT 75 PSI, what say you Musky ? ? , totally unsure myself ! ! ! !