It’s just 5000km year old bike, when I accelerate, it gives mix of white and black color smoke. What could be reasons and what royal enfield doing for this problem?
Your Royal Enfield may have been driven with some wrong fuel mixture, which in turn leads to smoke. As you have told, the new bike can also have some manufacturing defect and you should go to the official Royal Enfield service center and get the problem checked. They will repair it for free as its under the time period of engine warranty.