In replacing the exhaust and intake gaskets, what is the best approach for cleaning the cylinder and flange surfaces, avoiding any possibility of scratching? Basically just how clean is sufficient?
Also, in applying sealant for the muffler pipe-to-riser junction with the clam-shell clamps, where should sealant be applied?
My recommendation would be “NO” sealants RTV etc. Some use Hi Tack for setting intake gaskets in place. I would clean with a scraper and if needed a brass or soft wire brush, then wipe with solvent. Mating surfaces must be clean. Inspect to make sure that they are flat and there are no channels in faces if you had a blown exhaust gasket. Below are a couple of video links.