A professional railroad photograher once told me to pay attention to the background, as it can make or break a photo. I think if you shot your bike against a solid blue sky or green grass it would really bring out the black portions of it such as the seat and tires.
Here are some photos I took after getting my new bike. You can see that the weeds are a distraction and the afternoon sun produces shadows which hide the details of the bike. I need to return to the same spot in the morning when the sun is behind me and park the bike a little to the right so the weeds are not behind it.
Back in Black