dont put the y back on find a used D&D or BMP y paint that and put it on prob less than 70bucks used now days. let that 700 pump air.if not colapsed bad I would reuse it. I have pulled apart alot of f7 xf7 and only put new manafold gaskits on 2 of them and they had been pulled apart at lest 4 times {race motors] permatex both sides and all dognut joints and a bead on all the springs good to go
I don't silicone mine because I take it off too many times. I bought new gaskets for my 700 and it was $25, too much $ when I've taken it off 5 times in the past year or so.
What happens to me with my metal / gasket paper combo , if that's what you have ? is that the 2 stroke earl will seep past or spit past the flange and drop onto the belly pan or starter ? Jusat a thought. If all is flat and they are in good shape and sealed you probably are good.