heat from cylinders/motor deforms the plastic
not sure if these are right for airheads to sit above the cylinders. the two i have, the fuel fitting spots have completely gotten deformed to the point where one is almost clogged (they are oh less than 3 weeks old) but because the plastic is melting. the indentations or babs for the line on mine have completely smoothed out. its crazy! At $4 a pop, they need to be more durable than that. the fuel line ended up loosening and leaked fuel everywhere because the attaching points on the filter have gotten smaller!!