unfortunately, I did not remove intake hoses from crankcase so could not take good pictures of them however I did see (using torch) black gum stuck on track, on intake valves face & stem, fuel passage holes & throttle valves face. I am using fully synthesis oil SAE10W-40 (brand DP Racing oil) for the bike, it's quite hot & high humidity in my country (Viet Nam), "Excessive oily vapor from the crankcase" which you mean caused by lub oil?
- I can confirm throttle bodies had sticky after I removed cables and turned it by finger, it was hardly to open & slowly return by springs
-Yep, throttle cable lubrication also a problem in my case, I just can do it drip by drip and .......hope lube goes along with cable down to the other side of jacket sheathing. I'll buy one luber.
Thank you all for your helpful comments!