which petty?

[Super T.I.B]

im not going to argue with you super but go with what works best but a lot of problem stems from set up, our ducati dealer asks what type of fuel you want to run and tune to that fuel , as for fuel   European fuel is far better than anything we have here , like i said if your having problems it more to do with set up , by useing a lower octane fuel than you should causes pre ignition and pinging , and that my friend is not hear say thats fact , and im not having a go at you super im just pointing my view as a wrench and the fact all the fi bikes around here run fine on 95 -98 

Fair enough. 

I just don't know why you would pay more for fuel when you don't have to. Government gets enough money from us as it is. 

[Super T.I.B]

yes i know super , but if your manual says 95 run 95 if it wont run 95 you have two other issues , low compression or fueling problems , the octane rating is to do with compression ratios , the higher the ratio the higher the octane needed

Well there you go.

Looked at my little Ducati chart and the 1000 has a lower compression ratio than the 620. 10:1 for the 1000 vs 10.5:1 for the 620.

How does that grab ya? 

[bazz20]

  you have finnally seen the light anything over 9.5 to 1 should run 95 or higher

[Super T.I.B]

you have finnally seen the light anything over 9.5 to 1 should run 95 or higher

What? 

I have a 620, 10.5:1 compression ratio, I run 91.

You have a 1000, 10.0:1 compression ratio, you run 98.

The 620 has higher comp than a 1000. Or are my eyes deceiving me. 

I just don't get your logic.   

The OP has a 620, nearly everyone here who has a 620 has told him to run on 91, all except for Jukie whose bike runs well on 95. But Jukie only runs on two speeds, 0 & Flat Out! Even Ducmonrob has a 1000 and he runs 91.   

Horses for courses I suppose, if you want to give more money to the petrol companies and government when you don't need to, go right ahead, knock yourself out. 

[Super T.I.B]

And to add further, this is from Wikipedia, a reliable source of info  :

The octane rating is a measure of the resistance of gasoline and other fuels to detonation (engine knocking) in spark-ignition internal combustion engines. High-performance engines typically have higher compression ratios and are therefore more prone to detonation, so they require higher octane fuel. A lower-performance engine will not generally perform better with high-octane fuel, since the compression ratio is fixed by the engine design.

I don't think the 620 is considered 'high performance'

In most countries (including all of Europe and Australia) the "headline" octane rating, shown on the pump, is the RON, but in the United States, Canada and some other countries the headline number is the average of the RON and the MON, sometimes called the Anti-Knock Index (AKI), Road Octane Number (RdON), Pump Octane Number (PON), or (R+M)/2. Because of the 8 to 10 point difference noted above, the octane shown in the United States is 4 to 5 points lower than the same fuel elsewhere: 87 octane fuel, the "regular" gasoline in the US and Canada, is 91-92 in Europe. However most European pumps deliver 95 (RON) as "regular", equivalent to 90-91 US (R+M)/2, and some even deliver 98 (RON) or 100 (RON).

The manual may be printed for the States because of there crap fuel. 95 is really 91 over there. 

Higher octane ratings correlate to higher activation energies. Activation energy is the amount of energy necessary to start a chemical reaction. Since higher octane fuels have higher activation energies, it is less likely that a given compression will cause detonation.

It might seem odd that fuels with higher octane ratings explode less easily and can therefore be used in more powerful engines. However, an explosion is not desired in an internal combustion engine. An explosion will cause the pressure in the cylinder to rise far beyond the cylinder's design limits, before the force of the expanding gases can be absorbed by the piston traveling downward. This actually reduces power output, because much of the energy of combustion is absorbed as strain and heat in parts of the engine, rather than being converted to torque at the crankshaft.

A fuel with a higher octane rating can be run at a higher compression ratio without detonating. Compression is directly related to power (see engine tuning), so engines that require higher octane usually deliver more power. Engine power is a function of the fuel as well as the engine design and is related to octane rating of the fuel. Power is limited by the maximum amount of fuel-air mixture that can be forced into the combustion chamber. When the throttle is partially open, only a small fraction of the total available power is produced because the manifold is operating at pressures far below atmospheric. In this case, the octane requirement is far lower than when the throttle is opened fully and the manifold pressure increases to atmospheric pressure, or higher in the case of supercharged or turbocharged engines.

Many high-performance engines are designed to operate with a high maximum compression and thus demand high-octane premium gasoline. A common misconception is that power output or fuel mileage can be improved by burning higher octane fuel than a particular engine was designed for. The power output of an engine depends in part on the energy density of its fuel, but similar fuels with different octane ratings have similar density. Since switching to a higher octane fuel does not add any more hydrocarbon content or oxygen, the engine cannot produce more power.
However, burning fuel with a lower octane rating than required by the engine often reduces power output and efficiency one way or another. If the engine begins to detonate (knock), that reduces power and efficiency for the reasons stated above. Many modern car engines feature a knock sensor – a small piezoelectric microphone which detects knock and then sends a signal to the engine control unit to retard the ignition timing. Retarding the ignition timing reduces the tendency to detonate, but also reduces power output and fuel efficiency.

Most fuel stations have two storage tanks (even those offering 3 or 4 octane levels), and you are given a mixture of the higher and lower octane fuel. Purchasing premium simply means more fuel from the higher octane tank. The detergents in the fuel are the same, Premium does not "burn cleaner."

I'll shut up now. 

[Betty]

But Jukie only runs on two speeds, 0 & Flat Out!

Its known as a digital riding style 

[Betty]

The manual may be printed for the States because of there crap fuel. 95 is really 91 over there. 

I think you have that one around the wrong way ... if it was printed for the states, you would actually need to increase the octane rating to match our standard ... that is, printed as 95 for America would be significantly more in Australia so 98+ would be the recommendation.

Your source also lists 95 as 'regular' in Europe and we use the same rating system apparently. So, again, if we are using the same rating system 95+ would be accurate here. If our fuel is crap by comparison you should probably increase our local octane rating again to compensate therefore 95+.

But I love this quote the most:

Most fuel stations have two storage tanks (even those offering 3 or 4 octane levels), and you are given a mixture of the higher and lower octane fuel. Purchasing premium simply means more fuel from the higher octane tank.

So the whole argument is pointless ... apparently it is the same fuel anyway 

[Betty]

Obviously I am far from an expert but those wiki quotes from Super also would suggest that a learner legal (restricted) 620 should prefer the lower octane:

When the throttle is partially open, only a small fraction of the total available power is produced because the manifold is operating at pressures far below atmospheric. In this case, the octane requirement is far lower than when the throttle is opened fully and the manifold pressure increases to atmospheric pressure, or higher in the case of supercharged or turbocharged engines.

It's all far too complicated for me, but I will try and simplify:

. Put fuel in
. If bike runs OK then the fuel is probably OK
. If bike doesn't run OK, try a different fuel and repeat complicated analysis procedure

[Big T]

. Put fuel in
. If bike runs OK then the fuel is probably OK
. If bike doesn't run OK, try a different fuel and repeat complicated analysis procedure

Works for me tooooo Betty......... Is what I did...... 

[bazz20]

yes with out sounding  like a smart ass there is a couple of flaws in supers final quote
all road going vehicles have now been yousing a standard measurement the world over now called r o n, research octane number
our fuel is not alowed to be mixed coming out of different fuel tanks , thats highly e legal , what is written on the pump thats what that fuel is
he  dosent class a 620 as high performance , im shaw ducati would beg too differ
most f i bikes can be tuned to idle and run on all octane ratings , but you will lose performance
final note do what i did and be honest with your self and see how many kay out of a tank you get on the same road at the speed on diferrent  fuels , it cost me 30 cents more to fill up a tank of 98 to 95 but i get 40 kays more to a tank so 30 cent more works out a savings
ps betty your dead right , with any engine that not turbo or supercharged the air is at a constant pressure as you would have learnt while doing your diving ticket , boyals law that air pressure is 14.7 psi  so to put things simply engines do not suck in air they create  a negitve vacum so air forces its self in that why turbos help to  force more air in more air the more fuel you can burn hence more power 

[monstermick58]

. Put fuel in
. If bike runs OK then the fuel is probably OK
. If bike doesn't run OK, try a different fuel and repeat complicated analysis procedure

Yup!

Lets see, lets give it six months, say around May, and we will all ask the same question again




                                                Mmick (being a dick)

[DUCMONROB]

Yep, that was me.

There is a listing of manufacturers/vehicles on the Federal Chamber of Automotive Industries (?) website, the list saying whether those vehicles could/could not use the ethanol blend. Ducati was not on that list so I informed NFI about it and I also asked them if Duc's are suitable to use the e5/e10 blend. And NO was the answer. They didn't know that they were not on the FCAI list and were going to fix it.

As of last week, they are still not on that list.  

And there is news that ethanol blend is being rolled out to more service stations, replacing regular unleaded. The BP around the corner from my joint does NOT have regular unleaded!  

I have been told the ethanol causes the new plastic tanks to swell. It seems this is a good thing for extra capacity but no good for your paint work.

Rob

[bmroxm5]

Obviously I am far from an expert but those wiki quotes from Super also would suggest that a learner legal (restricted) 620 should prefer the lower octane:

It's all far too complicated for me, but I will try and simplify:

. Put fuel in
. If bike runs OK then the fuel is probably OK
. If bike doesn't run OK, try a different fuel and repeat complicated analysis procedure

excellent. thats what i think i'll try.
just don't want to err.. 'foul the plugs' in the process.

But i will stick to 91 for now 
Thanks everyone.

Feel free to keep bantering over it though 

[Betty]

excellent. thats what i think i'll try.
just don't want to err.. 'foul the plugs' in the process.

But i will stick to 91 for now 
Thanks everyone.

Feel free to keep bantering over it though 

Geez whatever you do, don't listen to me - I'm full of shit ... and have absolutely no mechanical knowledge.

[Super T.I.B]

Put diesel in it and see what happens.