This thread from 2 yrs. ago shows what the stock bushings & carrier brackets look like after a few yrs. of abuse!!!
http://www.buggymasters.com/forum/showthread.php?t=1107
Since I had sooo many karts here I just robbed a set and made a new swingarm then. We put some serious wear on them as they were used too. The ones I have now on the Yerf are solid steel-1-1/2" round with 1/2" hole in the middle, and they're holding up VERY well.