A year isn't so bad. But life is funny and one year turns into 5 faster than you think!!

Take the batteries out and on a float charger, put them on stands, grease the fork tubes/chains/anyhting that might rust, and I'd flush the fuel with REC 90 or anything ethanol free. Put the gas thats in them now in the car or lawnmower. It's a PITA with that many bikes but I have had no luck with Sta-bil lately. Even just 6-8 months!!