I have a 04 KLX110 for my son also, and we dont have that problem, our problem is the opposite, he is 8 years old and he cant kick it himself cause its too hard for him we had a PW80 before this and he had no problem kicking that.
A couple problems we do have is, it is VERY hard to start the first time, it takes 5 or 6 kicks just to get it to think about starting then usually 5 or 6 more to actually get it running the FIRST TIME that day. But once its started and warmed up it starts GREAT the rest of the day.
Another problem we have is if it falls over on the left side the oil we run out the crank case vent hose.
The first time we took it out, he washed out the front twice in turns and fell on the left side after 2 falls enough oil came out the vent hose that it was below the min oil level.
J