The most common and most likely answer to this crossword clue is the 4 letter word RODE
I've seen this crossword clue in The Times
R
O
D
E
More clues leading to the result RODE
Buddy explains!

The straight part
We know that "Came by bike?" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case came by bike? = rode.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does RODE mean?
RODE verb- To transport oneself by sitting on and directing a horse, later also a bicycle etc.
- To be transported in a vehicle; to travel as a passenger.
- (chiefly US and South Africa) To transport (someone) in a vehicle.
- Of a ship: to sail, to float on the water.
- To be carried or supported by something lightly and quickly; to travel in such a way, as though on horseback.
- To traverse by riding.
- To convey, as by riding; to make or do by riding.
- To support a rider, as a horse; to move under the saddle.
- To mount (someone) to have sex with them; to have sexual intercourse with.
- To nag or criticize; to annoy (someone).
- Of clothing: to gradually move (up) and crease; to ruckle.
- To rely, depend (on).
- Of clothing: to rest (in a given way on a part of the body).
- To play defense on the defensemen or midfielders, as an attackman.
- To manage insolently at will; to domineer over.
- To overlap (each other); said of bones or fractured fragments.
- To monitor (some component of an audiovisual signal) in order to keep it within acceptable bounds.
- In jazz, a steady rhythmical style.
- The line from a vessel to its anchor.
- A raid; an incursion.
- A roadstead.