Just in case anyone is still using the old cloth covered fuel hoses. Don't!
I have been persevering with this stuff for the sake of originality, renewing every year as the ends split but it is now unusable. I have just removed my ones for routine replacement and found that the inside diameter has increased from 7mm to 9mm, probably as the ethanol content in fuel is being increased to 10% well ahead of the "official" date. Fortunately, I use good quality fuel hose clamps but I have seen some bikes where the hoses are simply pushed on. They will fall off!