I know nothing, but I like to say what I think when I look at the photos here, so
the 1st one with B&W background I like it
, prefer it to the full colour, gets the bike totally the focus of attention, makes it real and full of vitality and the background becomes just background, like it is when you see them, can almost hear it, expect to snap my neck round to watch him go past. Great catch too, with the back wheel just clear.
sidecar on B&W, no, not enough vitality to the sidecar, the glossy black of the sidecar and the grey of the leathers doesnt lift it enough from the background, also I reckon the background is too blurred for this treatment, possibly a sharper more detailed B&W background would suit? or the whole photo in B&W or . . . colour, where I suspect the reverse effect of the base shot is better, the sharp black and greys of the outfit against blurred green tunnel, keep the background in colour but maybe faded out slightly?
3rd one, I find my eye pulled to the guy with the black hat, the solid black of the hat shirt and sunglasses is too strong for the rest of the background, the boots below him to an extent too. Fade him a bit or recrop so there's more to the left of him or so he's totally gone.
feel free to ignore me