Personally, I wouldn't breed a snake with a kink--you never know if it might be genetic. Unless you're sure the kink happened because of an injury or something, there's great potential for it to be passed down and if someone buys an offspring that looks normal but can have kinked offspring with the intention of breeding, well, you just royally screwed them over. >.>
In regards to your question, it should depend on whether the kink is above or below the vent, and how close it is. I'm sure someone with more experience will come along and offer their two cents.