That's progress! I'd still bet that once you get that screw out your problem will be revealed and it will be an easy fix.
The kits usually give you a spark plug tool that will also remove the nut that holds the drive sprocket on. I found that it's not the best tool to tighten the drive sprocket because it is awkward to use. I sheered the woodruff key after my first few rides because that nut wasn't tight enough, even though I gave it all I could with that spark plug tool. So I went out and got a real socket to use instead, I was able to get the nut to turn quite a bit more with a real socket much to my surprise. Also, some blue loctite on the threads will help keep that sprocket and nut locked in place.....
Good luck with the repair/exchange......
The kits usually give you a spark plug tool that will also remove the nut that holds the drive sprocket on. I found that it's not the best tool to tighten the drive sprocket because it is awkward to use. I sheered the woodruff key after my first few rides because that nut wasn't tight enough, even though I gave it all I could with that spark plug tool. So I went out and got a real socket to use instead, I was able to get the nut to turn quite a bit more with a real socket much to my surprise. Also, some blue loctite on the threads will help keep that sprocket and nut locked in place.....
Good luck with the repair/exchange......