A little Marvel Mystery Oil should do the trick, perhaps a capful in each cylinder.
On an SOHC 750 there's a 24mm nut under the points cover that you can use to turn the crank with a ratchet, does your bike have anything like that? I know it doesn't have points, but....maybe the nut is still there... Hate to toast your starter if the engine's frozen...
you could always remove the plugs and roll the bike in gear too... or up on the center stand in gear turning the rear wheel with all 4 plugs out.
I figured I'd answer before the Mods moved your post.... Cheers.
