Sounds like your ring is still not seeding itself well. Yamaha makes a product called "Ring Free" that deposits through your fuel. Similar to seafoam, but probably a little bit better.
Does it make any knocking noises or sound like it's worn? I have a TT with about 500 hours on the top end; it knocks because the wrist pin bearings are shot, but I used the Ring Free and it alleviated a lot of the smoking, hot and cold. Even yet, rings for them are cheap.
Just make sure you put your cam in the right way. Last time I had a motor rebuilt, we screwed up and put the cam in 180 out. Luckily, rotating the points plate 180 alleviated that issue.
"The bold adventurer succeeds the best.” - Ovid
WTB: Plated KTM EXC450/525 RFS, Honda CRF450X, Suzuki RMZ450