How much ground clearance should I have?
When on the track 2 inches from the ground to the oil drain plug is about perfect when strapped. This will provide enough space between the ground and plug when coming down from a wheelie while still on the gas...as long as the bike does not slam down from chopping gas or hitting the back brake.
When riding on the street we like to have at least three inches of ground clearance. Depending on what you weigh, this can be done with the front strap loosened so there is no pull on the front forks. The stock ZX-14 pan does have a very low plug, so watch out for "pot holes" and speed bumps.