you cant really do it, its an arse, you need to remove the fan housing front and rear tin, cylinder head tin, inlet manifold carb etc, it will take a while and you will struggle the whole way. remove the engine its doesnt take that long and will half the time it takes to remove and refit the head
Seconded. The engine is light and easy to remove. I've had engine and gearbox still joined together in and out 4 times in 2 weeks. The gearboxes look heavy, but again they're very light.