Let me see! I do appreciate your thought process designing this (death trap). I'm sorry and don't mean to sound rude, but,
1) if you actually try to ride, push or both a nearly 700 lb FJR up that 8' long 2x6 or 2x8, it will break and the bike will end up on top of you.
2) if you managed to get your bike up there, it will undoubtedly tip over on you and again the FJR will use you for a cushion.
3) If the above two things don't occur, those cheapy plastic wheels will explode and the FJR will once again land on you ruining your day.
4) if the first three episodes don't occur and you get your bike up there, the legs will collapse inward, outward or both because of not properly being braced and the FJR will once again piss in your cornflakes!
5) and finally, if none of these thing happen and you get the bike up there successfully, your entire "Trojan Lift" will simply fall over on you and once again your bones will suffer dearly!
6) Oh yeah, let's not forget that if you manage to avoid everything mentioned above, when you are finished and try to get the bike down from there, one or more of everything listed above will occur and the FJR will crash upon you and you will once again be screwed.
Summary: If you use the I-bolt that you screwed into a ceiling joist to support your nearly 700 lb FJR, there is a chance that joist will break and your entire ceiling will fall upon you, breaking both you and your FJR most severely. And to add to this catastrophe, when your (i.e. wife, girlfriend, mother or SO) comes home to see what you have destroyed, they will take whatever is left of you and finish it off for good!!
Mind you, I'm not trying to be negative!!
Just Saying!!