Aye m4s4,
If the inlet rubbers are split then rejuvenation is out of the question.
I have not tried the wintergreen method! But 'Armorall' does a good job of restoring flexibility and lubricating the inlet rubbers when assembling.
So far as I am aware both 1JK-14453-00 (R/handside) and 1JK-13596-01 (L/handside) facing the front wheel direction, mounts for the carburettors are readily available either as OFE from your Yamaha dealer or as pattern parts from the likes of Wemoto and Yambits. The rubber connectors between the carburettors and the air box are no longer available from Yamaha or others unless you can find 'old stock', so far as I am aware.
A thorough clean and the use of some of this stuff might work,
BUT I HAVE NOT TRIED THE WHEEZE MYSELF!Self_bonding_oil_heat_resitant_tape or
Liquid_insulating tapeI hope this helps.
My regards, Bill