normal for these is between 110lb & 170lb cold compression (there are major diffs between motor designs)
are you holding throttle open (or removing carb & muffler) and pedaling fast enough to pump up your guage?
2-stroke piston-port have dynamic compression, higher RPM's produce higher compression because there's less time for the air to escape, your compression will change based on your RPM, port timing, intake (this includes air pressure, forced induction [if any], port timing, intake length, intake [carb throat and manifold] size + any restrictions), deck height, squish band/combustion chamber shape and size, any leaks, etc. removing your exhaust or intake could skew your results if you're trying to read compression that way. The muffler will add restriction, boosting compression, and removing the intake removes restriction, again boosting compression.
However unless you're cranking it by hand, you should get at least 60 PSI. 0 says there's a leak somewhere, most likely head gasket (which isn't uncommon at all, our gaskets are virtually garbage). Lapping the head (sanding it down smooth and even) will help. To be honest I'm not using a gasket of any sort after lapping (I didnt even use glass, just circular patterns on sandpaper on a tabletop). However I have used permetex copper as a head gasket, though its not recommended, once you torque down the bolts it gets squished out and some gets into the combustion chamber. However if you want to know, I ran a single bead around the whole gasket mating surface, as well as the bolts (to seal them off from the chamber). With my old setup, using an 18v B&D drill from walmart, using a 14mm socket & adapter turning the magneto bolt to turn the crank I read 60 psi last time I checked. However I havent tested since I got reeds, Puch Hi and re-did the cylinder ports... only because my roommate somehow left my compression gauge under the leg of my chair and I didnt notice when I sat in it.
