Thanks for your attention guys.

I have old ECU (version 00). I have contacted Yamaha dealer but they couldn't help because XTX was not officially supplied to my country.

I have played with CO in 0-80 range. And I can really feel the changes, but they are too complicated to describe. The only thing I can say that engine always have this "suddenly loss of power" after few seconds. I can see the word 'surging' (am I correct?) everywhere on this forum, but I can hardly understand what does it really means

Other thing I am worrying about is "revs are higher than idle for few seconds after I release the throttle". This thing occurred just a few days ago, so I'm afraid this is not related to ECU fuel maps or something. Looks like this can be related to "mass air flow sensor" (don't know how do you call it) or some intake air leakage or other mechanical problem.

And sometimes engine could just stop while I'm switching between the gears (was 2 times only, but anyway).

So the thing I am asking for is to tell me which of my problems are 'XTX native' and which are not normal. Don't want to kill my bike, but don't want to make panic without a reason as well

This is my second bike, and I haven't had such kind of problems with my old one. That's why I'm nervous.