I know that if you go from stock to fat bars like protapers you need a new handle bar clamp for the steering stem but would you also need larger lever attachment clamps and grips? Or do the fat bars taper out to the stock size at the ends and are only fat in the middle where the steering stem is?

Is it possible to re-use grips? or do you have to buy new ones when you get new handle bars?

 

The ends of the bars taper back down to 7/8" so all your components will bolt back on. You can re-use grips if you can get them off the old bars without tearing. Try rolling them back off from the center toward the end, it's worked for me a few times. If you need new grips, Oury makes an awesome set of ATV grips.