L. P. Wyman 
The Golden Boys Rescued by Radio [PDF ebook] 

This is one of a series (6) of the Golden Boys. It takes place in Maine. The two boys agree to go on a camping trip to help the government locate and find the smuggling route from Canada down into the US. This during prohibition. This book intended for the 12-16 year olds of the day. Typical 1910-1920 story. Kids go off. One kid gets captured by the bad guys. He manages to escape. They find the smuggling route. The government steps in to catch them and all is well.
They magically have an energy cell (invented in an earlier book) that powers their motorcycles and their pocket radios.