Query Approved

It seems very strange bro.But don't worry...Experts will solve your issue.
IMHO please inspect and adjust the carburetor,i think the mechanic have adjusted your carburetor to rich mixture for high performance and less mileage.
So to check this :
1.Open the spark plug of your bike.
2.Clean it thoroughly by a soft cloth.
3.And re-install it.
4.Ride your bike for around 10kms at the way you normally drive.
5.Now turn off your bike.
6.Let the engine get cooled.
7.Now remove the spark plug again and notice the tip colour.

BLACK AND WET - RICH MIXTURE.
SILVER - LEAN MIXTURE.
BROWN - CORRECT SETTINGS.

Check it out and update here.

If it takes you 40 minutes to ride 3km to your college, you should probably walk. You will probably end up saving 10-12 minutes at least (one-side).

The problem with short commutes is that the commute ends before the bike has the chance to warm up properly. I have faced this issue for a long long time.

The issue in your case is that the commute average speed is slower than the average Mumbaikar walking speed. No wonder you get such low FE. Traffic is one of the biggest reason which ruins FE. Try riding the bike on some open roads and then report the FE. I am sure there is nothing wrong with the bike.

Re: Are herewith mentioned reasons why my GS(50+KMPL) dropped to 35KMPL ?

I do not think that will have even the slightest effect.

I own a Yamaha Fazer 2012 model, bought in March 2012. Completed 50,000 KMs over it. I have been thoroughly negligent on its service. So far, the bike has had only one service at the service centre, and one at the local mechanic. All other tasks like oil change, filter change are also not done as per requirements. The only thing I am particular is about chain cleaning, lubing, tire pressures and battery water since my running is high. I always do tank full only at night around 12 to 1 AM. If I need to refuel during the day, I do just it with petrol worth Rs. 100 or maximum 200. Also, I never followed the engine break-in or run-in. Since the day I have set my hands on the bike, I have screamed it to 115 KMPH, its top speed. I use this bike for daily commute from Thane to Byculla, which is 30 kms(one way). The route has 15 kms of eastern express highway and rest is through high traffic suburbs. Including local errands and short joy rides, my daily running is in the range of 70-80 kms. I have Leo Vince GP corsa carbon exhaust and UNI conical air filters. I am a speeder, when the highway is free, I ride at 90+ kmph and above 110 kmph in certain suitable stretches. I usually do not coast.


I still derive an exact 40 kmpl FE from this bike
I have further derived 44 kmpl from this bike when I was using K&N conical filter, which makes the AF mixture leaner
I have also(and still do) derive 50 kmpl from this bike when I ride it below 50-55 KMPH. This figure has also been reported by other fazer/fz who do not speed beyond 50-ish speeds.

I I fill petrol around 2 PM, when the sun is burning hot, the FE reduces to 33.

Re: Are herewith mentioned reasons why my GS(50+KMPL) dropped to 35KMPL ?

The calculation of mileage is not correct. Fill measured amount of fuel(1-2 litres above the reserve will do) and run till you 'physically' hit the reserve(i mean when you have to use the fuel cock to use reserve volume). Note down the ODO. Fill measured amount of fuel (higher the better) and calculate how much kms it ran with the petrol you put.

Just taking one reading when most of the fuel is in the tank but not usable is showing this error in mileage figure.