At my place, i have noticed that normal unleaded is light orangish in colour.

Okay guys, let me correct my statement about colours. By now the whole country is supposed to serve Euro/BS III fuel. Right from BSII specification here is the fuel colour & Octane:

Unleaded petrol = Orange = 91 Octane
Premium petrol = Red = 95 Octane

This is a GOI directive but not sure if it is happening or if there are any special provisions to this directive that are added up later.

Does someone have any official information to confirm Octane numbers of Unleaded & Premium fuels in Euro III cities and elsewhere...

I guess I haven't noticed the colour of petrol off late! Will start noticing from now.

I am yet to find information on how carburetors go bad but I have heard it many a times. Even at this moment one of my cousins is using an old Bajaj 4S Champion that has run about 120K KMs. Re bored around 90K KMs along with a change to connecting rod and stuff (before doign this we could hear the bike coming by its rattlign sound from half a KM away ) but his mileage doesn't cross 50. He's waiting for changing the carb that costs about Rs 1700 it seems. He's shown it to 3 different mechanics and all of them checked the carb and said the holes have become bigger and it needs replacement...

dunno what that would really mean... he is defanitely not speaking about the jets!

Hmm... intresting! Still cant quite imagine what is wearing out... do let us know if you find out. If it were the jets, they can be replaced... but since that isn't the case, one can only wonder...

Decide b/w normal and premium petrol

Step1
Learn the meaning of the term "octane rating". A petrol’s octane rating means the measurement of its ability to resist "engine knocking:, which happens when the fuel in the engines cylinder explodes instead of burning like normal creating a small shockwave. If a petrol has a higher octane rating, it will be more resistant to engine knocking. A petrol’s Road Octane Number (RON) is a combination of different ratings for different aspects of the gas, and is used to distinguish regular petrol (which usually has a RON of 95) from premium petrol (around 98 RON).
Step2
Know that for many cars, filling them with premium unleaded as opposed to regular unleaded will make no noticeable difference to their performance and will be an unnecessary expense as practically no engines require petrol with a higher rating than 95 RON. Unless you are driving a high performance sports car, or using your car to race, there’s usually no need to choose premium petrol.
Step3
Decide if your car does actually warrant the use of premium petrol. Some cars with turbocharged engines, or racing engines with high compression require premium petrol as standard. Most high value cars, sports cars and cars from sports brands (for example a BMW or Coupe) will benefit from being filled with premium petrol, allowing them a greater performance and quicker acceleration, although it’s by no means a necessity.
Step4
Decide whether the other benefits of premium petrol are worth the extra expense. Premium petrol is known to cause less pollution and maintain a cleaner engine through the detergents it contains.
Step5
Learn the different names for premium and regular petrol so you can choose between them at your regular filling station--not all companies use the same terms. For example, the premium petrol in BP garages across the country is known as BP Ultimate.
Step6
Look for the most expensive petrol on offer if you want to choose a premium petrol. Premium petrol will always be by far the most pricey petrol available, costing an average of 10 pence per litre more than regular petrol, which will add a significant amount to the average tank full.

Source: http://www.ehow.com/how_2071067_choo...ar-petrol.html

@Tulsi: It would be beneficial for the whole community if you could kindly mention the source of the information posted by you. Plagiarism, like you must have known by now is not appreciated ANYWHERE.

^^^ something more India specific would be useful...

There will not anything specific for India. That is India.

I found IOC fuels to be the best.... with Xtra premium my ZMA feels a lot smoother but the engine tends get a lil hotter than usual. But i get more mileage when i use the regular unlead from IOC.

HPCL n BPCL fuels i think i pretty much the same but IOC is much better....

i always thaught that premuim fuel or branded fuel as it is called is normal petrol+petrol additive (like bhardal or iftex)

plz correct me if im wrong and tell us how they make this fuel or rather what is added to it if not the above mentioned additives....

^^^ Nikhil, they are trade secrets

^^^^^ rite brother and those mite be???? any idea???

The most important extra component of premium fuel is, I believe, the higher octane count. Octane count can easily be calculated for these fuels.

Higher octane basically means more power so that should theoretically mean lesser knocking, slightly higher power and some more minor advantages.

I usually get XtraPremium for my Pulsar 150 dts-i and I have clearly noticed the knocking reducing by considerable amount.

I don't really think there is a problem with the current methodology... But the amount that we pay extra for such premium fuel is something that we can never be sure is right...

@raunak:stock bikes dont need high octane fuels and they dont knock unless u have modded it...
using higher octane fuel doesnt give ur bike any extra horses jus ur psychological feeling..

@Pradeep:
Who said stock bikes don't knock??? Are we still talking about Indian bikes? Heck, are we still talking about bikes???

And, psychologically or not, I never felt the power increase myself... I used to think the power must increase and I was wrong... Only the knocking reduces considerably and there is no doubt that does happen... After reading about these fuels on wikipedia, I came to know that higher octane fuels resist knocking but have no power advantage whatsoever.

Btw, why don't we add a poll to this thread and see what is the experience of xBhpians with these fuels?

Well I would like to add my 2cents to this,

I've always wondered the same question like you guys. And basing this on high performance machinary I concluded that there was never a noticeable difference between the higher priced fuel's. Actually the quality of fuel makes much more of a difference. Rust and other *dirt* in the fuels have cost countless carb jams and injector cleaning sessions to me and many of my friends. Its till such a extent sometimes I feel I should take a "chai patti channi" along with me to the bunk to tank up. I always give a healthy dose of "bas doh chammach" octane booster to a tank full. Never had issues, I usually judge a book by its cover. The condition of the bunk is directly proportional to the quality of fuel supplied. There is no real way for us to determine at the point the octane rating of the fuel but atleast we can be sure its worthy of my bike. Usually sticking to a good bunk my bikes always ran fine. Also I have a friend who owns a bunk and he always keeps laughing about the fact that he force feeds people "premium" fuel. Which instead is just regular gas. They dont have a choice. Can say anything to him. Dont have a solution for it either.