You really have proven yourself as an excellent artist! I especially like the red color to the jet bike. I have no problem with what you have so far, but I'd say that if you were going for a fast looking jet bike, your best design would be the bottom left one, seeing as how it seems more aerodynamic.
This is only my opinion, but all I can say is, you did an awesome job on all of them! :attn:
Nobody felt like avenging your death. Sorry.