What is a motorcycle radiator cap?

A motorcycle radiator cap would be unknown to many Harley Davidson motorcycle owners, as it is only found on high performance motorcycles. The Harley V-Rod is an example of a motorcycle made by Harley Davidson with a radiator cap. Sadly, the V-Rod abandoned the archaic and outdated technology of the 1950s and thus has had to surrender to the presence of a radiator cap. Nathan