The Luton lad had his 2014 Yamaha YZF-R125 taken between 10.30pm on Tuesday, June 13, and 4am on June 14.
The bike was taken from the back garden and the garden gate lock was broken.
The Butely Road resident had added red stickers to the bike, which may have been taken off after the theft to leave the bike black.
The number plate was previously LD14 WNX but the family believe they have spotted the stolen bike. They claim that the number plate has now been changed to ED14 WNX, and the red stickers removed.
Bedfordshire Police are investigating. Call 101 quoting crime reference number C/25062/2017. Alternatively, call Crimestoppers anonymously on 0800 555 111.