Greetings All.
I have just had the carbie rebuilt on the FC grey, and I also busted the carbie spacer. The carbie rebuild bloke said that the spacers are no longer available, so I decided to find a replacement and came across this stuff.
12mm high density compressed fibro.
Its the right height ( well, 0.5 mm out but who's counting? ), very heat tolerant, and so far, hasn't leaked air or fuel. Scrap bits are available real cheap. It's easy to cut and shape, but do use a mask or respirator cause the dust gets everywhere. I may try and seal the edges on my one with something later on, but I'm happy with it's performance at the moment.
Hope this helps.
Cheers and Beers