The RoundLock has a 22mm pin which will fit through a majority of motorcycle brake discs but it won't fit through most scooter discs.

There's an easy way to work out whether a RoundLock will fit your bike. Get hold of a 1-pence piece, as this is exactly 22mm in diameter.

If you can pass the 1p through your motorcycle disc, you will be able to pass the RoundLock pin through the same hole.