leaky valve cover

Pretty self explanatory ...it leaks and was wondering how hard it is to replace the seal on it...it is a 1979 750 twin

The hardest part is (sometimes) scraping off the old gasket.

If the bike is being maintained properly with valve adjustment checks every few thousand miles, the gasket shouldn't be stuck (too much). Unfortunately, some people are mechanically unsympathetic, and never adjust valves. In those cases the valve cover may have never come off before and the gasket stuck (and/or the valves and seats are burned).

If that model has a mechanical (cable-drive) tachometer, the leak may be from a failed seal where the cable goes into the valve cover. That little seal and gasket are usually easy to replace, otherwise, what Nessim said.

A pic would help. How long have you had it?
Steve

A method for removing the valve cover to preserve the gasket. Remove all of the valve cover bolts except for the ones on the ends --- loosen those a few mms. Then tap the valve cover loose w a mallet & big screwdriver. After knocking it loose, loosen the end bolts a few more mms, then pry off the gasket from one of the surfaces (I used a good paint scraper). Then remove the cover & pry the gasket off the other surface.

This method might be useful in preserving a newish gasket, instead of replacing it every time the cover is off --- in that case you don't have to pry the gasket from both surfaces.

On the 81 650 there's plenty of room above the rubber cam end plugs to fit a big screwdriver into place to knock the cover loose without damaging it. Hold the screwdriver (or something blunt) firmly in place & give it a good whack. Use a mallet, not a sledge hammer.

Unless some moron used Permatex or something similar, you shouldn't have to pry anything. Remove the bolts, tap around the cover top, sides until it becomes loose with a rubber mallet. You can use a small block of wood and a hammer to lightly hit it enough to jar it loose. You shouldn't have to pry on it with anything thus damaging the gasket or what's worse the mating surfaces. Like I said a pic would be helpful.
Don't assume anything.
Steve

Not hard to replace, but if t's stuck in place: I use a blade of a pocket knife at the corners of the cover tapped in gently with a small mallet. If you have old rubber camshaft seals, they will leak. I run a thin bead of Ultra Black sealer along the area where the rubber seals are when I replace the cover.

Edit to add:

The 750 twins do tend to leak oil at the tach drive. Aso, every one I have ever seen seeps oil at the front of the head gasket which blows back around the engine and leaves the famous black scum line. That may look like a valve cover leak too.