I had the carb ultrasonically cleaned which is a great investment of $30 or so because it comes back super clean and since it's just water it doesn't
usually require you to replace any seals or gaskets.
Drained the old gas and polished the plastics with a little cheapy electric automotive waxer/ buffer and that SG1 plastic restore. Cleaned the air filter too.
And learned a trick. It felt like the power valve wasn't opening at same RPM each time and was sticking so I figured I'd have to pull the cylinder to clean the power valve (which is pretty messy and time consuming).
But here is the trick I learned: instead of normal gear oil in the case I ran ATF instead. Now because ATF is a emulsifier I believe it cleaned up the gummy goop in the power valve after running about a gallon or so of good gas through it, and it started opening at the same rpm every time and running really crisp.
I guess some guys run AFT in their gear case all the time, but I'm told the film strength and heat resistance isn't as good and so after a few hours I changed it back to Yamalube or Redline Gear Saver (whichever I had at the time).
Now I can't say for sure if that was what fixed it or if it was just the combo of running good gas with full synthetic premix and a clean carb that did it, but the explanation made sense to me as to why it would help un-goo the power valve.
I've been using a similar technique on my work vehicle where once a year you drain a quart of oil and add a quart of ATF to the engine and run it for 15 minutes or so before changing the oil and it supposedly keeps the top end ungunked and it's still running great despite having over a quarter million miles on it.
Cleaned up: I think it looks pretty good now!
I like the aluminum frame guards too!