Tygon is not the best fuel line..There is no reason to use anything larger than the small neoprene fuel line on any gasser..I run engines up to 150cc on Hayes products molded neoprene fuel line..No clamps needed, does not get stiff, works well for clunks in the fuel tank...The inside diameter is about 3/32..
I get it from Custom Injection in Garden Grove, Cal...714 554 0531...