Even AMC themselves admitted the early twins had excessive oil pressure when cold......... F.W.Neill says it can force the crankcase halves apart at the filter............So I would say if you are happy the let the oil warm up ,a considerable reduction could be effected,say a relief set at 50 lbs ,or even 45.................Its funny to think that the two AMC bikes ,were near opposites ..........Norton twins had zero filters ,or even gauzes,whereas Matchless/AJS twins had filters everywhere......that need to be serviced regularly
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Well. I think it that depends where you think the leak is coming from. I still believe it is from the dynamo interrface rather than the crankcase or filter joint. Looking at the PRV piston, I am further inclined towards this view. There are two small holes which would force the oil out in 2 jets of oil when it relieves. If one of those jets is directed to the dynamo joint I can easily see how it would leak at that area. So - my solution, block off one hole, and re-insert the valve with the one free hole pointing downwards, away from the interface.
On relief, PRV is pushed outwards, oil forced through PRV piston bore/holes into timing case as before. Only difference is pressure will not drop as quickly as previously - but then so what?