I am about to do the carb conversion from the hibachi carb. There is a plastic spacer under the carb, do I leave it or remove it when I put on the Webber and adaptor. plate? I am thinking it is for a thermal barrier, but that doesn't seem to make sense because water is allowed to contact the bottom of the carb which i think is used to heat the carb.

Also, if it matters it's on a 1986 Brat.

I've been going through this on my 87 Brat. The adaptor lines up with the bare metal of the intake, so everything Hitachi-related has to go away. I don't recall if mine had a plastic spacer, but the Weber kit parts stack up appropriately and line up: intake -> Weber adaptor gasket -> Weber adaptor -> Weber gasket -> Weber

i and others have actually drilled out the coolant hole in the manifold to suit a tap size M12 comes to mind, to then fill the hole with a grub screw or allen socket head grub screw to prevent any possible coolant leak issues when converting to other than the Hitachi