Yamaha XV125 Virago jerks lightly

Hello together, I recently bought myself a Yamaha Virago 125,EZ 2003 with 7.6KW. The machine actually runs cold as well as warm I would say quite well, jumps immediately. What with me problem is, if I drive e.g. 3rd gear and give full throttle swallows the machine for a moment and then accelerates normally. What I have to mention is that Yamaha accelerates better with 3/4 gas than with full throttle and that you can feel it so properly. According to previous owner, the suction support was replaced,larger Main nozzle installed and then carburettor set (as I said in idle it runs really nice and quiet). I just installed the new NGK Iridium spark plug, but set electrode distance to 0,6mm (according to the internet is 0,6mm). Candle picture looks fine for me. What else could the problem be?