Quoted from jeffspinballpalace:

Blackwater 100 and Banzai Run come to my mind. Two non-licenced motorcycle themed games which competed against each other in 88. Certainly one of them was created specifically as direct response after learning what else was being made. Both games are pretty different, and would hold different appeal to coin droppers. I don't know if it worked out or not, but back then buyers were Operators and Distributers, who tend to buy more with theme, deals, etc rather than how good a game was.
I think the theme was viewed with skepticism, as we've had exactly one motorcycle themed pin released since. Care to guess what that non-licensed title was?