Motorcycle mechanic

A successful gynecologist decides to fulfill his life's dream: give up medical practice and become a motorcycle mechanic.
So he gets out of the medical business and enrolls at a mechanic's seminar with Harley Davidson.
After many weeks of training comes the final examination, taking apart and then re-assembling a randomly chosen Harley engine.
He grabs his tools and sets to work, but soon he gets worried: while he is still working on the valve-covers, everybody else is already busy with removing the cylinder heads.
He falls more and more behind, and as he is just starting to put it all back together, everybody else is already finished.
He manages to put the engine back together, barely in time before the exam ends.
Because it took him so much longer than everybody else, he goes straight to the teacher to ask how he performed.
"Well," the teacher says, "out of one hundred possible points you scored 150." "But how is that possible?" the ex-gynecologist asks.
"Well, it breaks down to this: You get fifty points for correctly taking the engine apart. And you get another fifty points for putting it back together perfectly." "And what did I get those additional fifty points for?"
"For doing it all through the exhaust."