I have been restoring an old 82 Piaggio bravo I bought, I have cleaned the carb, replaced the air filter, and the fuel lines and petcock. When I went to try and start it, it wouldn't fire, so I got the compression checker out and it came to just short of 50 PSI. I'm no expert but I'm pretty sure that is way to low. Does anyone know what the compression should be, and or how to fix it? I did remove the head but there was no gasket. Is that possibly part of my problem?