I've got a non-AC heaterbox on my 1969 GS 400 and I know there are seal sets for them, but I can't find it on Rockauto. I prefer using only one company due to shipping costs to Europe. Are there people who made their own seals? If yes, how? The outer box has a ridge of 1/8th(-ish) inch so that would be the minimum thickness of the gasket. Or would it really be preferred to have a set?
You can use roll of 1/4 or 3/8 inch "a/c closet tape ". It is adhesive on on side, and pull off paper on the adhesive side. Used to seal air conditioner air handler closet doors in American homes. Also used as weather strip seal. The foam is similar to the type used to seal the heater core box. https://www.googleadservices.com/pa...6aDv1Lv5AhWJF1kFHTNHCWUQwg8oAHoECAMQEA&adurl=
Put a bead of Perma- tex or urethane on the flange and install the box. Use two stand-off pins to line it up and install easily without mess.