J'ai trouvé la réponse....sur un site US : Honda ne fabrique plus les manchons petit modèle...Obligé de forcer comme un malade pour installer le carbu et la pipe ou alors il faut acheter le filtre à air complet.
Sinon il y a ça :
http://www.hondaminitrail.com/ct70.html
Carb to Air Box Boot. Injection molded rubber boot WITH THE ORIGINAL CORRECT DESIGN. We have made this boot out of our OWN tooling and made sure that it is correct to the original design that Honda used. The Honda replacement boot, that we also sell, is not correct but can be used. The Honda boot is to long and must be forced to fit between the carb and air box thus causing the rubber boot to bend and force the air box and carb to mis-align. The NEW CHP boot design is 100% correct to the original design, allowing for proper installation of all mating pieces.