Starting/running issues with kx 125

Well, to start off i'll give u a bit of my bike's history. My bike has always ran a bit rich, but i can still run it with 42:1 yamalube without fouling plugs. The beginning of my issue is when i first noticed that if i left my gas on for around a half hour or more the bike would seem flooded and therefore be hard to start. After the first few times this happened, i discovered that if a turned the gas off, then tipped the bike over and drained some of it, the bike would start up. Since my dad is lazy and I don't know much about carbs and didn't want to take it apart, and didn't know what was wrong, i just decided to always turn off my gas when i stop.
Anyways, i went riding friday and the bike seemed to be riding like it always did for probably an hour. I was riding in deep sand and I started to notice that it seemed to be losing power. After a little while longer (ten minutes) i could definently tell that it was. That is when i stopped and pulled in the clutch to see what it was, and of course my engine instantly died. After that i couldn't get it started. My first thought was that i had fouled a plug, but that wouldn't make sense because i was running 42:1 yamalube and it had never fouled a plug w/ it before. I decided to check it out though anyways. I pulled the plug and it was a perfect tan color, as it should be.. so it wasn't that. I checked spark, the air filter, and tried doing my little flooding technique, but nothing worked. after having to get towed back to my car, me and my dad looked at it for a bit. My dad was able to finally get it started by holding the throttle wide open (which we had already tried before but this time it worked). So i took it for a test spin. it again seemed to be slightly weaker in power, if i had to guess it seemed weaker up top and similar still in low. throttle response still seemed decent. I brought it back to the car and killed it. and couldn't get it started again. after that we decided to pack it up and just head home.
when we got home we took my carb off and we opened her up. everything seemed fine. my theory was that the float height was too high, causing constant flooding, therefore causing lost power and hard starting. But we checked the jets and the float and they seemed fine, no dirt. i also checked the slide and the needle. they seemed fine. so now i think the problem lies in the reeds. Am i correct?
thanks for reading my overly detailed story and helping me out here! :)

bike has always started fine before this and the compression still feels strong. Are you saying that if i got a bigger pilot jet or main jet instead of smaller that it could solve my fouling problems?

i will look into buying a compression tester. i assume you can just buy them at sears or lowes? And my bike fouls plugs at 32:1 and not at 42:1 so what u said doesn't make sense to me. I know u think it's probably the top end, and i can see that, but lets assume that it's not for right now, then what would u say it would be?