I totally get wanting to have a fun background... while the shot is about the person/object, the background needs to be well thought out as it adds to the image.
The challenge as a photographer is ensuring the background doesn't take up more importance in your image than the subject.
1- shooting at a different angle
2- shooting tighter in to your subject to minimize the background
3- using flash to light the subject differently than the background
are three ways you can look at making the background part of your image and not the focus of your image.
You did (imo) a much better job in the second image, but i find the colours and various shapes and textures in the background catch my eye more than the solid colour of the bike.
And watch your foregrounds as well to make sure there is nothing that removes from your image..