Nothing major has gone wrong with this bike so far. Just the basic parts that gain wear and tear over 15 years.
I replaced the front brake cable, put new tires on it, and replaced the chain. But the bike still runs great and is a beast.
On any dirt bike, you can expect to add new boots, chain, replace tires, replace a stretched brake cable, tighten the rear shock, and change the spark plug. But no major problems beside the brake cable, which was replaced.
This is a great bike for beginners, and also if you want a good trail bike. It handles and drives great, can rebound a jump, and starts on the first kick (even to this day).
It is easy to use, I taught two people how to ride it and it took them only a few minuets to control and handle it. It can pop a wheelie, tear up a yard, and really be fun.
Honda makes a good bike, and if you are looking to buy a bike to ride around your yard or to go on trails with, this bike is great.