stuck slide only affect throttle change not choke settings.

and... you've cleaned out the main when you should've done the pilot.

Yep, most likely it is the pilot jet.  They have tiny holes, and they sit a bit higher than the main jet......so as the fuel starts to evaporate and leave gunk and corrosion behind, the pilot jet is the first place to get clogged up.

loosen the hose clamps and you can twist it towards you.
and it'll go 90° if you take the top off.

OK.....so this is another opportunity for me to show folks how obsessed I am with the crappy new fuel.

In hopes of avoiding the corrosion and carb gumming that can occur, I shut the petcock off before I get home.  I shut the fuel off when I reach the intersection at the bottom of the hill (about a mile from my house), and as I round the corner toward my driveway I can feel the bike begin to surge a bit, and by the time I pull in my drive and pull in the clutch, the bikes dies.  This method removes most of the fuel from the float bowl - so if you happen to have a string of bad weather or get busy at work......and don't get to ride for a while.....there is little fuel in your carb to go bad and start to plug things up.  The pilot jet doesn't go all the way to the bottom of the float bowl and there will still be a little fuel in there - but there will be a whole lot less and so far it has prevented any fuel problems related to a short storage period.

I don't do this while I am out riding - only on the way home when the ride is over.  It will take you a few tries to find a landmark near your home that is far enough away to allow the fuel to be used up by the time you reach home.  I am lucky that I have a driveway that is a pretty steep downward grade - so when the bike runs out of fuel I can just coast into the garage.  The slight bit of lean running is not harmful to the bike, as it is at low speed and only lasts a few seconds.  (If your carb has a drain screw on the bottom of the float bowl - draining the carb before storage is the best way to go).

The ethanol fuel does OK in modern fuel injected systems.  They are sealed up systems and not vented to the atmosphere like a carb with a float bowl is.  Things like lawn mowers, motorcycles with carbs....any kind of carb where there is gas sitting stagnant in a vented float bowl is subject to the damage the ethanol can cause.  The issue is that the gasoline portion of the fuel evaporates - and it leaves behind the ethanol in high concentration, and that causes corrosion to aluminum parts and dissolves some rubber parts.

High octane won't hurt it.....but like you say it really isn't going to perform any better in a low compression engine.

The supply of ethanol free fuel in this area is a bit weak, and I have to drive on a 3 hour round trip to get fuel from the Countrymark COOP in Liberty, Indiana.  I haul a 55 gallon drum (or 2) and buy the fuel for the chainsaws and mowers....it is rated at 91 octane.  It has the smell and yellow color of the gasoline I remember from my youth.  I add StaBil, and with it sealed up in the drums I can use it for 2 years and it still runs fine.  There are supposed to be a few marinas in the area that carry ethanol free fuel.....it is very seasonal and I have not yet gone to see if I can get my fuel cans (or drums) near to the pumps.

We don't have ethanol forced on us here and I never use it, but I still drain the bowl via the drain screw per Dave's description if I'm not riding it for a while. Hasn't done any harm...