If that new $47 worm gear assembly is the one from MikesXS, I'd pass on it. None of the parts interchange with originals because the angle of the swirl is different. You're better off sticking with originals. The female nylon part is what usually wears but Yamaha used that part on many models so it's pretty easy to scrounge them .....
https://www.partzilla.com/product/y...?ref=8e57f4c772a5cf9e21585bf1f084074551846d34
My dealer has a boneyard out behind his shop and while there weren't any 650s out there, there were several 360s, 400s, and 500s. I scrounged the worms off of all of them, lol. In fact, that's how I discovered the 1L9 worm. I have it installed on both my 650s and I've supplied them to a couple of my buddies for theirs.