403 Carburetter flange gaskets

[mikebro]

I've just rebuilt the carburetter using genuine parts. The Service manual tells me that the flamge gaskets are special harder material than standard and should not be replaced with ordinary ones. The rebuild kits have ordinary papare gaskets for the flanges. Originals are just over 1mm thick and of a hard black material. The new ones are paper and about 0.5mm thick.Anyone lbow why the Ser ice manual is so adamant about using these "special" gaskets?

On another subject, I was interested to find that the number 3 carburetter had a petrol inlet port that had not been drilled out like the others had. Since the port was still considerably larger than the orifice in the float valve, it probably didn't affect operation, but it was interesting to see what to me was a 67 year old manufacturing fault.