If it flips then that's extra cool points

I found that the easiest thing to wheelie is a Kawasaki KLX110. You don't need big power. All you have to do is find the balance point.
Practice on a dirt bike, on the dirt, away from prying eyes, so if (when) you flip it you can feel like an idiot all on your own. And wear good protection when practicing 'cos it does hurt when you fall off.
Don't do it on public roads 'cos you could die, or at the least be in trouble with the old bill. Unless you're good at it of course, in which case you should do it all the time, especially if you're riding a Kawasaki KSR110 in front of the school kids on the road that leads up to the office at least twice a day. They love it
