I need some help from ye old vintage guys. I have a vintage mx bike that I have been restoring and have been completely stumped in my options for a intake manifold and airbox boot. The parts are NLA in both USA and Europe, the few used ones I have found are in worse shape than mine, and I have never come across new pieces. Are there any secrets to repairing these? I don't know of any substances that don't further harden the rubber. Thanks for any help.