My chain tension keeps loosening up after about a half hour into my riding jaunts on a Sunday afternoon. I even have one of those roller skate looking aftermarket chain tensioners attached to the footpeg, but it doesn;t seem to help. Could it be that the bearing carrier is worn? Cause I have to re-tighten it about every 30 minutes. Any answers would be appreciated.

 

First make sure your axle bearings are nice and tight with no slack. Is you chain and sprockets good. It could be your pinch bolts are loosening and your bearing carrier is turning. Try using a black permanent marker and mark the bearing carrier and axle with a line after adjusting the chain and making sure the pinch bolts are tight. That way you can tell if the bearing carrier is turning on you.

 

If you had to put an aftermarket tensioner on that means that some thin is wrong. Try taking off the peg mounted tensioner and see if your chain is stretched out too long,for normal adjustment. If not remove the bearing carrier and check the condition of the bearing carrier and the swing arm it self. If they are scored up bad enough that will cause it to not hold the carrier in place. It is a simple design not too many things can go wrong with it.
I dont recommend a tensioner like what you describe, if it was on a 125 or a 200x maybe. But youa riding a 350x, which has unbeleiveable torque,ya know?