My nephew has a 2004 trx400 electric shift on the last couple of rides it is making a grinding sound when going around corners it used to do it if it was on a big lean going in or out of a hole now it grinds just going around a tight corner any ideas what it is

 

bad ball joint and the cv joints are rubbing... just a thought

 

Sounds to me like you have a bad wheel bearing. When you go off camber or around a turn it throws extra weight to the opposite side. Thats a good sign that you have a bad bearing. Lift it off the ground with a jack if you have one and you will possibly feel loose motion in the wheel that has t he bad bearing.

 

It does sound like a wheel bearing. If so, now is a good time to upgrade to a set of Highlifter sealed bearings. To make installation easier, stick the bearings in the freezer overnight before installing to make them easier to tap in. Also, FYI If they drop right in without any resistance you probably need to replace the knuckle assembly.