ORIGINAL: RCIGN1

Hayes black seamless neoprene will NOT slip off a straight piece of brass tubing...It needs NO clamps...It WILL work with ANY size gasser used on ANY engine...Don't knock it if you haven't tried it...There is no reason to use tubing any larger on any engine, including 150cc twins...
My test stand has a fuel tank made from a backpack blower conversion...I put the tubing in it last year sometime...It is immersed in fuel 24 hours a day, seven days a week...It't still as flexible as the day it was put in..
I don't know where the notion that 1/8 Tygon is required got started, it's not true...