Black Smoke problem in Honda Shine 2007 model?

i have a bike from honda known as shine and it is now 5 years old clearly and i purchased it on 2007. It was working well in terms of mileage and maintenance stuff and i didn't get a single complaint apart from the tyres changes. But now when i ride my bike above 70 km/pr it starts producing smoke which i thought firstly that it will be a minor problem but now at the speed of 40 it is also outputing smoke what to do. Please help.

I think there must be some problem in the engine, you should go to your nearest mechanic and sort your problem out.