A clapped dirt bike means that the dirt bike is not in good condition and has seen better days.
When a dirt bike has been clapped out the dirt bike has not been maintained properly and is in need of major repairs or the dirt bike may also be completely destroyed.
Clapped out dirt bikes are usually a few years old or older.
The same goes for even a car, truck, motorcycle etc and if it's clapped out then it's not in good condition.
Clapped out is another meaning for something that is in need of repair and is not in good condition.
You could have a clapped out car, clapped out motorcycle, clapped out truck, clapped out lawn mower etc.
But most times clapped out refers to dirt bikes and motorcycles that are in bad shape.