Checked with a car and found out that when I was overtaking it @ 105km/hr, it(car) was on 99 km/hr. So I think it's ok till 104-105km/hr. This time could go only till 112km/hr. Will check again for 110+ km/hr

So you are assuming the cars speedo is 100% accurate?.

This is going to be a long thread with no single "right" answer.

Will also try with a different car and also trying to drag with my friend's Duke till the end. Anyway a line has to be drawn. Top speed of Fz-16 in normal road conditions.

Was caught on the same type of Car which I had mentioned above on the cop's speed camera and the speed was exact 83km/hr (speed limit was 80km/hr). So taking the face value, the speed may not be right infact but surely can draw a line where people claiming 120km/hr + speeds on a FZ-16. Some have even taken the video of Fz-16 reaching 130km/hr on stock condition. Isn't that funny?

It is an industry wide known fact that car speedos are MUCH more accurate than motorcycle speedos. How much? On average all motorcycle speedos are erroneous by 15% whereas car speedos are inaccurate by only about 3-5%. So comparing by a car seems very much reasonable to me as it may not give you the true value of the statistic but WILL decrease error.

I guess we all should stick to the topic and answer the top speed on fz or fazers speedo and life will be simpler

So you still want to use a inaccurate car speedo as your baseline reference.....Wow you guys never cease to amaze me
Like I said, this will be a long drawn out thread based on too many variables.

Get a sat nav/ proper GPS plotter. Fix it to the bike. Pick a spot and mark 2 lines start and finish a few kms apart.
Drain each fuel tank completely. Pour in 5L fuel from a large fuel can. The same fuel for each bike.
Put in new spark plug (per bike) and new airfilter (we'll leave the oil change for the serious people)
Record your tyre pressures before and after.
Wind speed, direction, Temp, ground temp, Humidity, barometer reading.
Do 5 runs back to back and record each top speed.
Same rider, same clothes + helmet, same weight. Keep it as constant as possible.

Get proper instrumentation instead of halfassing around. Cut out as many uncontrolled variables as you can.
Get as much data as you can before you start, then you can work out relationships.

If you want to be serious instead of mickey mousing around then do something similar to this otherwise you will be wasting your time. That way you can say Here is my data, Make your own interpretations to those who doubt you. Using a already known non calibrated device (in this case the vehicle speedo) to measure speed from is a waste of time and petrol.

Get some people together who has a personal GPS, or even a Tomtom incar nav. Get a bunch of friends together and share the roles. Make it somewhat like a test day at the track, You can play race car/bike engineers for the day

^^^ @Mad Mik; Why are you wasting your time and effort? You are assuming that most of these guys who are testing are doing it out of scientific curiosity/ measuring the performance of their bikes. Once you go through the thread one realizes that this is not about testing, its about bragging rights, its about inflated egos and who has a bigger pair of b***s....

I know but there is always hope. I know nothing will come of it hense my previous messages of this will be a long drawn out thread.
Basically a pissing contest. Who can pee highest up the wall.

First two answers one by Moderator and the other by prince are most convincing. Rest all (most of them not all) just want to poke with their mouth but not with their heart.

Having said all that. Let's assume all favorable conditions to the bike. Right temperature, right altitude, right wind direction. What would be the bump say maximum 5km/hr? Some guys are claiming to have got more than 120+. There is a youtube video of some guy touching 130km/hr. The point is how far it can be pushed and not how favorable the conditions must be. The point is whether the speedo is accurate after 115km/hr.

I will try and explain the issue with speedo errors in as simple words as possible. Speedo error is normally considered in terms of percentile units. Let us suppose that a bike is showing 40 km/h on the speedo and the actual speed is 36 km/h i.e. an error of 4 km/h.

So what do you suppose will the error be at 80 km/h? 4 km/h? No, it will be 8 km/h!

Therefore, the actual speed at the time that speedo is indicating 80 km/h is 72 km/h!!! This is because the speedo error is 10% and is not a constant 4 km/h. Therefore, if the bike is showing 120 km/h with 10% error the actual speed will be 108 km/h.

The crux of the matter is that speedo error is not constant in terms of speed across the range, it is constant in terms of percentile units.