We used to do this many years ago with our triumphs and BSA's. I used to take the tank s off and drain and clean them,just to be safer. Of course they were smaller lighter and easier to manuver into a house than Harleys.
Just make sure there is absolutley no gas in the tank or carb and fuel lines. And no fumes.
It could be a deadly outcome if not! If there is any Gas in it at all, any vapors that escape will lay to the lowest point in the basement and may find a source of ignition like a furnace or water heater, washing machine ect. And that's not good.
If your bars are too wide, you may be able to unbolt them and wrap a towel around the tank and lay them at an angle. Usually there is enough play in the cables to get them in line enough to clear a door jamb. Then you can bolt a cut down pair of bars or a piece of the same diameter pipe back in the dog bones or handle bar mounts, that will enable you to steer if and hold it to guide it in the house.
If you have a really damp basement, Moisture can be a concern also. It can rust things in a few months like slip on's and such. Good luck.