2D Motorcycle Side Scroller

Hello,
I am currently working on a 2D motorcycle game for mobile but I have not gotten very far due to a few major problems. First off I would like to say I have tried using the prefab of the side scroller but the character controller limits me to only having the bike collide in one spot. My second idea was to just try to make my own using a polygon collider,rigid body and the side scroller movement script but that failed because there was no gravity. SO if anyone has any ideas that would be huge help I have looked all over the forums and answers section for answers but I have not been able to find anything. And one final thing the game I am looking to make is going to be relatively simple not crazy realistic.

Thanks in advance

 

Sometime ago I was thinking about making a racing game too. These liks should point u in the right direction:

http://www.unitymagic.com/shop/en/unity-two-wheeled-add-on.html
http://forum.unity3d.com/threads/18807-Motorcycle-stabilization/page2

 

Okay Thanks