KYBO is in the 1970 edition of Eric Partridge's Dictionary of Slang and Unconventional English (volume 2), where the entry reads:
Jonathon Green's 3-volume Dictionary of Slang lists KYBO, with KIBO as a variant.
There's a long definition-cum-description of KYBO here: www.urbandictionary.com/define.php?term=kybo It runs as follows:
Following up the scouting lead takes us to the scouting website www.scoutorama.com which has this definition for KYBO:
A wimba wet a wimba wet a wimba wet In the Scout camp the mighty scout camp the Kybo calls tonight.
Hundreds of worn-out kybos end up abandoned alongside Iowa byways, destined never to relieve another cyclist.
Kybo beat Birds Nest in the Christmas Hurdle at Kempton in 1978 and in the Champion Hurdle the following March was going strongly in second place, just behind Monksfield, when he fell two out.
Gifford always maintained Kybo would have won had he stood up, although that view is not supported by the form book.
Beacon Light, Birds Nest and Within The Law were all making their presence felt at this stage, but Champion brought Kybo moving threateningly through on the run to the second-last.
There is no greater battler in the game than the diminutive Dessie McDonogh-trained favourite, but even he had met his match this time as Kybo fought off his renewed challenge on the run-in, passing the post with daylight to spare over his dogged rival.
Kybo, travelling like a winner, misjudged the second-last completely and slithered to the floor, leaving Monksfield and Sea Pigeon - again - to fight out one of the epic finishes in Cheltenham history, the former prevailing by three-quarters of a length.
Kybo: moved through threateningly going to the second-last GERRY CRANHAM