Blimey, one never stops learning, thanks!!!!!!

There is actually, as ethanol has less energy per litre than petrol. So the more ethanol they blend with your petrol, the less energy you're getting for your money!

V-Power (or any other high octane fuel available at the pumps) is created by blending. There are only two ways to increase the octane number of a retail pump fuel: One is to put special additives into the fuel which discourage pre-ignition (lead compounds of old), and the other (current method) of blending high-octane fuels in with the ordinary petrol. Shell (of any other refiner) can't afford to, and don't, refine tens of different specifications of petrol, so what they do is refine a standard petrol (longer chain alkanes) and a very high octane version created by the process of Zeolite cracking (creating short-chain branched alkanes), reforming and isomerisation, the two are then blended together to obtain the required RON number.

The shorter the alkane chain (and the more branched), the higher the octane number. However, the volatility of the hydrocarbon increases with decreasing chain length. So in a nutshell, your V-Power fuel actually contains more "volatile stuff", but is at the same time more resistant to compression auto-ignition! :sleepy1:

thought I'd check the bike's handbook....recommended fuel is Premium unleaded only....with a RON of 95 or higher

also found this on Wikipedia.....

[Most fuel filling stations have two storage tanks (even those offering 3 or 4 octane levels): those motorists who purchase intermediate grade fuels are given a mixture of higher and lower octane fuels. "Premium" grade is fuel of higher octane, and the minimum grade sold is fuel of lower octane. Purchasing 91 octane fuel (where offered) simply means that more fuel of higher octane is blended with commensurately less fuel of lower octane, than when purchasing a lower grade. The detergents and other additives in the fuel are often, but not always, identical]

That's written from a very American perspective, their fuel being generally slightly lower octane, but also rated by (MON+RON)/2, rather than RON as in Europe.

As you can see here:
http://www.freeimagehosting.net/newuploads/bxa5h.png

The first lot, I was just putting standard fuel in. Then, you can see three fuel-ups with Tesco Momentum 99 (avg 63mpg), followed by my last fuel-up of Shell V-Power (returns to 56mpg)

What is happening here exactly?
Anyone care to comment?

Lots of things can effect fuel consumption, ambient air temperature, tyre pressures length of journey and road surface. I used to work for shell and could get more miles to a tank from shell fuel than I could from tesco fuel. As i understand it tesco and other supermarkets put higher levels on benzene in their fuels to give it the octane level but that is not so good for economy. I never buy tesco fuel anymore though this momentum stuff sounds worth a go!

If you want to be realy anal then change gear at low revs, accelerate gently put nitrogen in your tyres as its more stable than air and is not effected by temperature as much so will increase mpg and improve on tyre wear.

personally, ride it like you stole it and have fun!!!!!!!