How safe are the chinesse frames

[Eli]

How safe are the chinese frames

I was wondering can any body tell me how safe the frames are on these pit bikes.
I had a x-18 midi bike and after 2 summers of riding the frame cracked, it was a good thing i noticed it or it could have been realy bad for me. I have a banshee pocket bike it is is very well made, and i am very happy with the quility. I want a second bike to take to the track and was thinking of getting a pit bike and turning it into a mini motord, but am having trouble getting good pictures of frames, i know with the cheaper bikes you are going to get crappy welds, so i do not mind spending more. i have read a lot about the engines, so i am good there. i am trying to spend about a 1000.00 on a bike but you can not get a good 150cc for under 1300.00 in the U.S. so i might just buy a 125cc, (these are around 800.00 shipped with a 125cc ) and update the engine later. i weigh 185 lbs, i will not be jumping with the bike.
can anyone give me a couple of names, (they might be called something different here) of what to look for in frame quility or some pictures so i can try to match them up with the bikes here

 

[bigs_11]

have a look at dhz dpro 140 ive herd good things

 

[I_THUMP]

Theres plenty of frame pics in this thread http://www.miniriders.com.au/chinese-mini-s/26333-pit-bike-frame-p-rn-7.html

or this one lol http://www.miniriders.com.au/chinese-mini-s/28411-pit-bike-frame-destruction-pics-2.html

 

[FMX_22]

Your using it for motard ??( there won't be that Mutch stress put on the frame

 

[motovertmachine]

got a friend in hospital atm after snapping a head stem coming down a jump on chinese bike! not smart