oil leaks

As stated in the title i have a 1980 cb750 with dual cams, i recently purchased the bike with unknown miles and have very little knowledge of these bikes. It has pod filters and was tuned for them, the left side breather hose had a plug in it which is something i will fix but i am having a few...

I have a '78 CB750 and I can't seem to figure out why once the bike gets hot it pours oil out the left rear case cover which houses the shifting mechanism and oil pump. Originally I thought the gasket was to blame, so I used black rtv oil gasket create-a-seal. That worked for just couple rides...