How do I find the master link on a Mongoose Intake dirt jump bike? I want to switch cranks on my Mongoose Intake dirt jump bike but can't find the master link
There is a good chance that there isn't a master link. Many single speeds do not have one on the factory installed  chain. It requires a chain tool to press out the pin. At that point a master link can be installed or a replacement pin can be installed using the chain tool. The chain does not need to be removed to change the crank unless it is worn. If you are changing crank or chain ring sizes you will need to either shorten your existing if it is serviceable or replacing it if its worn or too short.