Hey, cool character design. Though if I understand it correctly, he's on two wheels? Seems to me like he'd fall over.
I did an edit:
Try to make it look more metalic by adding sudden/bright speculars and ambient light popping up in the shadows. Also there's a number of colours in the palette which are unnecessary, such as having 2 ambers, the olive, the almost-black grey, etc. You could chop down a bunch of colours, really. I played with a few of the colours mentioned.