Sharp turns fast

Is there an easy way to tell if you're falling in turns because you're trying to hit them too hard or if your technique is bad?

Our practice track has a 180 turn that's only about 12 paces wide. I'm trying to hit hard because theres a jump right after it and I can't get into w/o downshifting to 1st. I'm trying to get into 2nd coming out so I can be winding out 2nd coming into the jump (If I hit 2nd any later the bike is popping up bad coming off the jump). But when I hit the turn hard like that I'm either going over the berm (about 2-3 feet high) or laying it down. I'm up on the tank with elbows up. Any suggestions or comments?

Thanks!

The bike I'm riding is a CR125. The problem is the track right now is so small (its a friends private track and were waiting for more dirt to expand it). It has 3 180 degree turns that are only about 15 feet wide and I can't seem to keep it in 2nd and keep enough power?