My honda activa has started losing mileage just after 2 k km - what should I do/check?

Initially my activa was giving around 40 km/lit, in city conditions, but since last 100 km the mileage has dropped down to @ 25km/lit; also if the engine is left idling the speed drops and then the engine stalls/stops. Could it be a dirty carburettor or/and something else. I have not changed the grade of fuel or the petrol pump station. Also this has come to notice since my last free service, done in June'14.
Any help will be greatly appreciated.

Service center probably messed up your carburetor settings. This is why I never give to them idiots. Also check whether you have proper engine oil level and grade

Sounds like it may need a tune - take it back t othe dealer & if the problem arose just after your last visit make loud noises until you get satisfaction

The mileage dropped immediately after a service? Take it back and get them to check out what they did.

Normally activas don't have engine meter. So i would recommend you to get installed with it. Or give your activa for servicing and don't put overload on engine. If you do so then the mileage will increase gradually.

Check your carburetor settings and take proper maintenance for author parts for high mileage

The problem was a dirty idle jet of the carb. Now my activa is back on track!