Ok so I just purchased a 97 banshee yesterday and I noticed that the crank case has this part cut off and looks like jb weld or something in the hole.
http://www.partzilla.com/parts/search/Yamaha/ATV/1997/BANSHEE+-+YFZ350J/CRANKCASE/parts.html
It's the part that the #23 bolt goes into on the crank case. It's cut off and ground flat and then just sealed up, maybe I will get a picture today if needed as well. I'm wondering what exactly this is, and is it a big deal where I should start looking for another case. Seems to run fine and all that of course but i'm just a little freaked out now.