IME, the issue isn't pressure because pressure is simply an indicator of resistance to flow. I am sure that you already know this so only trying to establish context. I've been struggling with a means to assess oil flow volume to the camshaft area, and especially to the right exhaust journal.
As several posts have asserted, there seems no issue with camshaft life in the KLR as produced, unless oil volume is near zero. Pdwestman's photo of a piece of swarf in one banjo bolt hole reminded me of another partially plugged banjo noted on a thread some years ago. This indicates further that the oil supply seems to be adequate.
Any indication of the flow volume to the cam bearings at the 5 PSI noted? KLR oil pressures at the test port are often < 10 PSI when warmed up and running on highway, IME. This likely translates into something lower to the camshafts but haven't been motivated to measure as noted earlier that there seems no pattern problem.
I absolutely agree with klrphile, that too oil delivery low can result in burning cam journals and share the concern which seems to be suggested that opertaining below the safe limit has very serious consequences. No one offered a valve cover for construction of a window or camera port and am beginning to lose interest as there seems little profit in pursuing the investigation in the light of no pattern of failures excepting when oil is low. Maybe missing something but there seems little prospect of improving not apparent camshaft problems.
Pdwestman's oil consumption hypothesis is interesting to follow and consider however we lack data to differenciate oil consumption causes. It may be that reducing oil throw off will reduce oil consumption in some engines but this may be a matter of reduced oil delivery which does not cross the short term failure boundary and helps to address oil consumption by partially starving the lower end. No matter where I go in thinking about this issue, I must return to the problem in evaluating the oil delivery volume and that of assessing the oil delivery necessary. I have noticed no data.
One major difference in systems between that of the KLR650 and that of the huge number of automotive and commercial engines in which excessive throw off was the basis of oil consumption. As I noted in posts elsewhere, replacing piston rings with refinished cylinder walls did not reduce oil consumption sufficiently in the cases in which worn main bearings were flowing too much oil. In the case of the KLRs of which I have been familiar, these started using oil at some mileage quite subsequent to new. There seemed to be no discernable wear to connecting rod big end and, regardless, would not expect a rolling element bearing's oil flow rate to significantly change, unlike an insert type bearing.
If forced to pick a position to defend, it would have to be that the oil consumption issue is a piston ring/cylinder wall oil control issue rather than excessive oil throw off. That said, still more than happy to do what can to assist Pd's investigation. If his hypothesis is correct, it may be possible to reduce oil consumption issues in affected engines without disassembly. One has to like that even if it seems a faint hope. That, and there's nothing better than to find that one is wrong.
Finding one is wrong and that's better than being right....sounds like a good definition for marriage.