Stang,
Your right on about the bike "loading up" with oil while trail riding 1/4 ~ 3/4 throttle and then "Cleaning it out"
with a wide open run.
The oil & unburnt fuel collect and then get blasted out when you open her up.
I wouldn't go any leaner on your main just yet. You can clean up the bottom and midrange by raising the clip position on your needle,(lowering the needle in the seat leaning out the fuel/air ratio) and or a smaller pilot, or both.
I wouldn't go any leaner on your main just yet. Get your mid range dialed in a little closer and then have a look at the main again.
The only reason I say that is that the circuits do all overlap at some point, and the pilot circuit is always open.
So leaning out the pilot some more is gonna affect the main to some degree (although it may be a small amount)
And the same goes for the needle, The ankle bone connected to the shin bone kind of thing.
Make your next adjustment, run the bike through the gears and get it up to normal operating temp.
Adjust your air screw for the best throttle response you can get and ride!
I copied this plug chop test description from
"Spankys Jetting Guide"
" The easiest way to test it is to do a throttle-chop test. With the bike fully warmed up, find a long straight, and install a fresh plug. Start the engine, and do a full-throttle run down the straight, through all gears. As soon as the bike tops out, pull the clutch in, and kill the engine, coasting to a stop. Remove the plug, and look deep down inside the threads, at the base of the insulator. If it is white or gray, the main is too lean. If it is dark brown or black, the main is too rich. The correct color is a medium-dark mocha brown or tan. "
You still have a few other adjustments you can tinker with after you feel your bike is running as good as possible with what you have to work with now.
You can still change the throttle slide and different needle tapers. Now those are not cheap by any means, but I guess the point is there is still alot more tuning available to you should you choose to.
There should be less and less oil on your fender and the pipe joints as you continue tuning the carb and the Bikes performance should be getting noticeably better.
Keep tabs on your water and tranny fluid levels as they can also give you a fit if the seals start leaking.
You will soon be able to tell what the bike is telling you it needs by how it's running.
You are making progress Stang, Maybe not as fast as you would like , but hang in there!
Tuck\o/