Improvised performance on your bike! (4)
I believe the answer is:
scat
'improvised performance' is the definition.
'scat' can be an answer for 'performance' (scat is a kind of performance). I am not sure about the 'improvised' bit.
'on your bike' is the wordplay.
I cannot really see how this works, but
'on' could be 'at' (I've seen this in other clues) and 'at' is found in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for scat that I've seen before include "Shoo!" , "vocal style?" , "Get away with cats" , "One way of singing" , "Jazz singing - animal droppings - silvery fish" .)