You will need the following:
1 - case of good beer
2 - bottles of good liquor, appropriate mixers, ice
4 - bottles of good wine
4 - reliable, relatively able-bodied men (4, minimum)
2 - very pretty women (2 minimum, preferrably flirtatious)
You will need to do the following:
1. Take everything off the bike that comes off easily; tank, seat, battery, wheels, especially wheels, etc.
2. Put the beer, wine and liquor in your apartment.
3. Go get the pretty women and hide them in your bedroom for use later.
4. Call the relatively able-bodied men to come over.
5. Show the men the beer, wine and liquor.
6. Surprise the men with the pretty women.
7. With the men's help, remove wheels if not already removed.
8. Position pretty women at the foot and head of stairs.
9. Tell men to each lift a corner of the bike and carry, in lock-step, up the stairs. (3 foot steel rods through the axle carriers makes it a snap)
10. Start drinking and admiring the bike. (Take everyone to dinner later if you are unable to feed them at your apartment)
What's posing you the problem is leaving the wheels on..... you're trying to go up, the bike is trying to go down, and it has weight, and more than a little physics, on its side. As we say in the space business, "Gravity is tough". Without the wheels, even if you have to unexpectedly set the bike down, it's not going anywhere..... it'll just rest there on the steps.
The beauty is, a) the men need not be sober for this operation, and b) men being men, no one is going to set their corner down first in front of pretty women (assuming the heterosexuality of the men).
Anyway, that's my $0.02 worth,....... lose the wheels and incentivize the participants.
Happy New Year,
Rod