I put an aftermarket oil radiator on my 1983 R65 a few years ago and used the parts reguired at the oil filter for retrofitting for a cooler like a 1989 GS and have had two aluminum radiators pop and leak. The last one was tested from the factory at 150 #. I'm putting a rad from a cruiser BMW and it looks a bit more robust. I put an oil pressure guage on it and will go above 100# at high idle easily. That is with 20-50 castrol at about 60 degrees F. on the highway at 4500 rpm and oil temp at 160 the pressure is still 100# The oil pressure relief valve is supposed to be the cam chain tensioner and is supposed to open at 75#. The parts fiche shows the tensioner piston pushes on the tensioner and the spring goes in the opposite end and into the cylinder in the timing case. Is there a chance this diagram is backward? Seems to me the relief piston head should face the block and the oil pressure pushing it out until it pushes the piston out far enough to uncover oil relief holes and drop the pressure. Any Ideas?