My youngest is on an 02 KTM LC 50. I just ordered from Chaparral a pair of Renthal KX 65 bars for $39.95... a great deal. They're 28.14 inches wide with not much pull back or serious rise. My neighbor's kid bent his bars on his SX 65 the second day out ( my kid just had to bang bars with the 65 and they both went down hard). The neighbor cut a pair off a Honda 650L and they work great! I'm guessing the stock SX 65 bars are around 26-27" wide so a pair of renthals wouldn't be that much wider. I think the extra width on my son's LC 50 will help him with steering stability when coming off jumps and smacking bumps, rocks, etc. Good luck.
Dennis