I took the pipes off altogether. Then I took them down to a local auto shop. There I matched the diameters with a couple of “Frost Plugs”. I ensured they would be a tight fit. A quick smear of Locktight Blue and I tapped them in. I was very careful not to disturb the flange gasket. At least I assume that’s what it was. All in all it took 2 hrs including the trip to the shop. I was very suspicious of the join at the headers but there seems to be no leaks. Just got back from a ride. No leaks. Running fine. There doesn’t seem to be any change of power. Just the exhaust note. A bit sharper and flatter.