Turn the engine over with either the crank bolt at the front or the alternator bolt on the back. You could be feeling resistance from the kick start mechanism itself. Having to tear in to one of these isn't the best. Although Wingovations is getting more bearings than we used to be able to find.
Take the heads to a machine shop. Have them cut the seats and surface the heads. Replace the worst valve/valves and then lap them to the new seats.
While there you also have them check the valve guides for wear. Have them check the valve stems too. Do not let them grind the valves.
1975 GL1000 parts bike (parts for sale)
1976 Goldwing Super Sport
1985 Honda Elite
1976 KZ900 Dragbike
1992 ZX7 Dragbike (KZ900 style motor w/NOS)
and a rotation of various purchases
Randakk approved Carb Rebuilder