Go by bike, covering length - yay! (4)
I believe the answer is:
whee
I'm afraid I can't even guess how this answer relates to the clue.
Can you help me to learn more?
(Other definitions for whee that I've seen before include "Expression of delight" , "I'm going downhill, fast!" , "Exuberant cry" , "Exclamation of excitement when going fast" , "What fun" .)