I'm stuck at the Old Mine Road bike fights, I've got all weapons and the goggles now except the booster, but no matter how long I ride the road, the guy with the recoil booster never appears.

It's been a few weeks while since I picked up this game again, and I remember getting the recoil booster already in a previous fight. I forgot, can you lose the booster again if you lose a fight?

That is wieed,because you cannot lose the booster once you have it.
But haeve you got the hovercraft lifter? You cannot jump the gorge without that.
Hint: Go back to the wrecked Fertilizer truck and look at it, very closely....

I completely forgot about that part :) I picked it up at the crashed hoovercar site and installed it on my bike.
However, when I tried to steal the ramp again from the cavefish cave, it still won't let me.

Edit: nvm, I figured it out :)

CENSORED BY GOG

If you don't have the booster and the hovercraft lift;Ben just says his bike does not have the power to jump the gorge.....

That's just one of the puzzles in the game I think, you're not supposed to get the booster off him.