Ok. my sportster will not crank. It will turn over and if I put my hand over the carb it will fire up for a 1-5 seconds after that It's just the sound of the starter. What could cause this?
I'm gonna guess that the bike has been sitting for a while and this is the first time you've tried to start it?
It sounds like the carb has a plugged jet. When you put your hand over the carb it increases the vacuum in the air horn of the carb and pulls the fuel through. It also reduces the amount of air that's allowed into the cumbustion chaimbers so it will enrichen the air/fuel mixture. If it's a newer model with a vacuum petcock make sure the vacuum hose is connected and in-tact. Remove the fuel line from the carb and make sure the petcock is on and that fuel is getting to the carb from the tank. You will likely need to disassemble the carb and clean it with some carb cleaner.
Also check the intake seals.