Get you some of this:
https://www.yamaha-motor.com/yamalube/categories/maintenance/21/shop-supply/3...
I was dubious about it til I used it. Now I see the light. It's just amazing this stuff. You can put all your parts in it(best), or throw the complete carb in. It doesn't damage rubber parts. After use, you can put it in a container and keep it to use over and over.

She runs now! The engine sounds pretty smooth and quiet, which is amazing for a thumper. I'm hoping that also means I have a few weeks left to check on the cam chain tensioner

I'm pretty sure the issue was the float needle's "spring" being completely stuck. I also found some other gunk in one of the air jets.

The only thing left is to double check the float height. I'm pretty sure it's OK (I don't think I bumped it), but it's better safe than sorry. The Clymer notes on checking/setting the float level are a little confusing. Does anyone have a better illustration of how to measure that?

Thanks Dave!