Yes, you are right. Main fuel line for a stock Blaster's carb and crankcase vent are 1/4" ID. Vent lines for the carb are 3/16" ID. Pingle/Banshee petcocks and some aftermarket carbs use 5/16" ID fuel line. I love Moose Racing line clamps, BTW...got a whole variety pack and use them everywhere, even on lawnmowers and my buddy's Timberwolf 250.