No, not a stupid question. You could buy a compression gauge with a rubber nipple on the end of it, (cheapest one) or spend the money on one that threads into your spark plug hole. Compression is checked through the plug hole (with plug removed) , the problem with the cheap one is you need to hold it firmly against the head and not let go until you get a good reading (takes two people). With the more expensive ones, you can screw it in and let go of it while you're kicking the bike over. Napa or any auto parts store should have them, remember to bring your plug with you so you get the correct threads. Cheap ones cost about $35, you can find the threaded ones for about $60. - bjawes