Every 3000 Kms Oil Change, Greasing wheel Bearings, Greasing the Chain, Cleaning the Petrol Tank (usually during rainy season there is a chance of water getting mixed in petrol)
You get a solvent to mix in the engine oil which makes the engine oil thick, usually I observed that I get a good mileage when I use that, recently these went out of stock & using the oil without it, when I used it, I usually got my bike serviced after 4000 kms, its a new bike & I brought it on 1st Jan 2013 & it has ran till 12k kms till now.
I havent googled about it, Its my experience coz I have a Two Wheelers Spare Parts & Service Station, hence I get some liberty to do some R&D
I have a Commuter Bike HERO HF Deluxe & running is 60 kms daily & I get mileage of 70kms per Ltr. If I ride below 50kmph.