I have a 73 roadster with a fiberglass tank. I'd like to change it to a metal tank. The cutout over the top tube is smaller at the rear on the metal tank. Is this normal? It appears that the fiberglass tank has a lower profile. I don't want to buy one until I know for sure. This is all due to the new fuel eating my fiberglass. Thanks.
73 were normally not supplied with glass tanks. All genuine commando tanks will interchange on the frames. There were a few inferior roadster metal tank pressings but they are rare... and I am not referring to the new production india tanks. The smaller opening will not likely be an issue.