Now that we have a sprocket let's keep it on the output shaft.The output shafts are case hardened steel-this takes the majority of us out of the loop for having the right tooling.The best way to accomplish this is to take the output shaft to a machine shop and have them drill and tap threads for you. But I'm going to give you an alternative! By adding that extra 1/4" to the shaft you have room enough to weld a nut on the end of the case hardened output shaft. Since the load applied to the new sprocket isn't where the bolt is this will work and keep you well within your working & tooling element. My output shaft had a center machine hole so centering the nut was easy as sharping the end of the bolt to sit in the hole.I protected the splines with a piece of tubing-I cut a vertical slit in it just incase I touched a weld to it and needed to get it off easier, like the lid on a canned ham! An old cutting disk was the perfect size to protect the bearing seal.A little grinding to clean it up and some careful filing of the end splines we now have threads for the retaining bolt
of course make sure that the new sprocket installs smoothly by hand.The retaining bolt only needs about 12 lbs applied to do it's job. You can use blue loctite if you have any fear or if your sprocket didn't weld up straight and wobbles.