Years ago, I used a motorcycle storage system called a "Bike Barn". There are probably several different makes on the market now, but it ran me about $250 new, on Ebay, kept the bike dry and in good condition for the 5 years I used it , was easy to get the bike in and out of, easy to maintain ( a little canvass waterproofing once a year) , and was in good enough condition what I finally got room in the garage, that I resold it on Ebay for $100. Took about an hour to set up, initially, but worked really well.