Oil leak

I just purchased a 71 cb750 and there is an oil leak which seems like somewhere upper left I have not really examined it closely yet but my question is does the engine have to come out of frame to say remove valve cover and if so it seems like a bear to accomplish thanks

Yes it has to come out. More than likely the rubber nickle seals under the cam towers are leaking.

FWIW...I do recall frame modifications "kits" to allow top end removal in frame were available in the past...maybe not anymore.(?)...or maybe people are reluctant to cut frames as sohc machines appreciate in $