So, this is my third build. I'm using a random cruiser frame and an old engine that I pulled off a friends bike when I rebuilt his motor bike. I changed the cylinder body and piston as well as replaced the muffler and gasket, carburetor, and spark plug. I had it running and took it out around town. I stopped and turned it off for about an hour. When I tried to start it again, it wouldn't run. I should note that during the ride it blew the exhuast gasket because the nuts had come loose. I have since replaced the exhuast gasket, cdi, and magneto coil. It still won't run. I have checked everything I can think of. I suspect its not pulling fuel into the engine, but I'm not positive. Is there anything you can suggest, my fellow gearheads, or should I just get a new engine?