Hey there BuddyLee, just thot I'd share what finally fixed mine. I have the same quad and had the same issues.
Replaced regulator-didnt fix it
Adjusted valves-no better
Cleaned carb-no difference
Then when I was putting the carb back on I noticed a small hole in the intake tube between the carb and the head🤨(looks like it got too hot once and melted a little) so I got some high heat gasket maker and smeared the hole shut and perfect, throttles all the way up, lots of power and running sweet!
Idk if this is any help just thot I'd share