Hello this is BabyFatalis (i know it says it on its own but its fun to say. I dont read any strats i come up with my own ideas. Heres two strats that will/should help.
1. .
(Fun with explosives 101) -a YKK takes 7-8 Lrg Barrel bombs to kill
-flash bomb it
-stand behind it and to the left of its tail (so spin wont stop you, this is YKK's sweet spot as u have time to get out of the way every time)
-place 2 LBB and detanate with a SBB
-run (it will most likly frenzy)
-combine more LBB while YKK is mad. and wait for frenzy to end.
-repeat.
2.
Twin Bladed Doom -Wait for YKK to charge and run up behind it.
-blast it with the charge mode super att.
-continue hitting until YKK turns around.
-run and repeat This one takes patience but ive beaten the YKK without being hit.
Hope this helped