The trouble is alot of folks might not even be able to tell if their bikes detonating on too low an octane till the damage is done (and it doesn't take much on a bike). Kawi recommending the higher octane is just a way to "play it safe" so to speak. Keep the engines together for the common folk who wouldn't know the engines grenading underneath them till it locks up and throws them on their head. I think its actually a pretty smart way to help the non-mechanical types keep their bike together longer. Not all factory recommendations have evil motives lol.

I'm pretty sensitive to sound and vibration in my bike, but I can't say I would recognise preignition. Is it really that subtle or is it a matter of paying attention or not paying attention?

If high test leaves residue and "regular" has potential to damage, howabout midgrade, like 89, as a compromise? No one has mentioned 89.

If you install a device to advance the ignition would that promote the preignition problem?

So many questions!

Yep, recon we are on a different scale, we only have 95 ron and super unleaded, and of course ours is more expensive per gallon, at £1.03 per lt = £4.63 per gallon= approx 8 us for the 95 ron but the brit gallon is slightly more.
B-A

BadInBlack, I am not saying the book is wrong. But engineers write what is called white papers stating the high and low limits for any given part of the bike. Those white papers are passed on to folks that decide what balance to publish depending on what spin they are trying to put fourth. That version is passed on to writers who will make a rough draft of the book. Lawyers will then review that copy to tone down areas they are concerned with. I'd bet there are not many lawyers that are also engineers. So I would also bet their concerns do not match those of the engineer. That draft is passed on to management to refine what ever spin they decide should be made. Might not happen just as I described but I'm sure it's close.

Long story short I would love to see the original white papers V/S claiming the owners manual is the golden book.

Then throw on top each bike is going to be a little different. So you can not make one "single statement", I.E. run 90 octane fuel, and it be the absolute truth for each bike. You, the owner of the bike has to decide what is best for his bike.

Okay-then I guess my bike with a 4 degree advance on it would do just fine with 87.Yes?

Philness I agree...in the end it does come down to the owners choice, unfortunately not all owners are educated enough about bikes, mechanics ect to always make the best call on their own. I think even the manual just "recommends" 91 or higher...it really is the riders choice

And 07, you're bike will be even more prone to detonate on 87 with 4 degree's of advance. I wouldn't run anything less than 91 in that beast. Thats one benefit of higher octanes, you can advance the timing more to gain more power, works on N/A or boosted motors

And Sharkey same thing, advanced timing=more prone to detonate on lower octanes. Its not too hard to hear detonation if you're listening, but if you don't know the symptoms and brush it off thinking its nothing, it doesn't take long to hammer you're engine into submission. Just not worth the risk imo

And 07, you're bike will be even more prone to detonate on 87 with 4 degree's of advance. I wouldn't run anything less than 91 in that beast. Thats one benefit of higher octanes, you can advance the timing more to gain more power, works on N/A or boosted motors

Ivan has my timing turned forward as far as the Ignition Module will allow down low and tappers off the higher you rev. Kind of like a down hill ski slop. I have NEVER had a ping running on 91, all though he recommended 93 if I could get it (to be safe). 91 kind of runs close to the line for the advance I'm running. So I guess if you want to play the Hp game you could keep dropping down till you here the pinging or the hint of a ping then go up one grade. Or play it safe, still be the best bet.

Has anyone ever heard spark knock with our bikes on any grade gas ? Or get bad gas from a crap station ?

Sharkey wrote:

If high test leaves residue and "regular" has potential to damage, howabout midgrade, like 89, as a compromise? No one has mentioned 89.

That's my idea with choosing 89 and not going all the way down to 87. Still, I see there are situations where people have certain mods and it seems most prudent to stick to the higher octane. Same goes for more severe operation of the motor when it's more likely that residual fuel could ignite on the wrong stroke.

I had detonation once on my last turbo bike, it was a combo of too much boost, not enough octane (I shoulda had race gas in it instead of premium pump...my bad lol), and an air-cooled motor running in very high ambient temps. Other wise I always run the recommended octanes and have never had any other issues....and thats been spread out over almost 30 years and LOTS of diff machines

Okay-I'll stick with 91,92 then.Thanks all-good info!!!

Hub is right as there is only so many BTU's in a gallon of gas period no matter what you do unless you add more BTUs in.
I normally run 89 as thats the sloest to 91 in my favor by the book . dont find many 91s here so I geuss 2 clicks down is better and you dont get more BTUs out of one over the other, now hot day and Im by the ocean I will do 91 but I have not had my bike pinging yet

I've ran 87 in my bike, even since the thin head gasket (which btw raises the compression substantially).

I can tell you guys that you will NOT run into detonation problems on a stock motor'd bike. It will actually run much smoother and produce a little more power.

If you are running an ignition module or an advancer, yes you might run 89 or 91 if it helps you sleep better at night.

I'm with Slow, run nothing but 87 and have never had any ping. I'v had more then one motor builder tell me to run the lowest octain you can without pinging and all will be good.

interesting reading:

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 are used in more powerful engines, since such fuels explode less easily. 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,[citation needed] 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 motive 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.
The octane rating was developed by chemist Russell Marker at the Ethyl Corporation c1926. The selection of n-heptane as the zero point of the scale was due to the availability of very high purity n-heptane, not mixed with other isomers of heptane or octane, distilled from the resin of the Jeffrey Pine. Other sources of heptane produced from crude oil contain a mixture of different isomers with greatly differing ratings, which would not give a precise zero point.
[edit]Regional variations

The selection of octane ratings available at the pump can vary greatly from region to region.
In the Rocky Mountain (high altitude) states, 85 AKI is the minimum octane, and 91 AKI is the maximum octane available in fuel. The reason for this is that in higher-altitude areas, a typical combustion engine draws in less air per cycle due to the reduced density of the atmosphere. This directly translates to reduced absolute compression in the cylinder, therefore deterring knock. It is safe to fill up a car with a carburetor that normally takes 87 AKI fuel at sea level with 85 AKI fuel in the mountains, but at sea level the fuel may cause damage to the engine. A disadvantage to this strategy is that most turbocharged vehicles are unable to produce full power, even when using the "premium" 91 AKI fuel. In some east coast states, up to 94 AKI is available [1]. In parts of the Midwest (primarily Minnesota, Iowa, Illinois and Missouri) ethanol based E-85 fuel with 105 AKI is available [2]. Often, filling stations near US racing tracks will offer higher octane levels such as 100 AKI.
California fuel stations will offer 87, 89, and 91 AKI octane fuels, and at some stations, 100 AKI or higher octane, sold as racing fuel. Until Summer 2001 before the phase-out of methyl tert-butyl ether aka MTBE as an octane enhancer additive, 92 AKI was offered in lieu of 91.
Generally, octane ratings are higher in Europe than they are in North America and most other parts of the world. This is especially true when comparing the lowest available octane level in each country. In many parts of Europe, 95 RON (90-91 AKI) is the minimum available standard, with 97/98 RON being higher specification (being called Super Unleaded). In Germany, big suppliers like Shell or Aral offer 100 RON gasoline (Shell V-Power, Aral Ultimate) at almost every gas station. The United Kingdom also offers Shell V-Power, but in a 99 RON octane rating, and Tesco fuel stations also supply the Greenergy produced 99 RON "Tesco 99". In Australia, "regular" unleaded fuel is 91 RON, "premium" unleaded with 95 RON is widely available, and 98 RON fuel is also reasonably common. Shell used to sell 100 RON petrol from a small number of service stations, most of which are located in capital cities (stopped in August 2008). In Malaysia, the "regular" unleaded fuel is 95 RON, "premium" fuel is rated at 97 RON, and Shell's V-Power at 97 RON. In the Netherlands Shell V-Power is a 97 RON (labelled as 95 due to the legalities of only using 95 or 98 labelling), whereas in neighbouring Germany Shell V-Power consists of the regular 100 RON racing fuel. In other countries "regular" unleaded gasoline, when available, is sometimes as low as 85 RON (still with the more regular fuel, 95, and premium, around 98, available). In Russia and CIS countries 80 RON (76 MON) is the minimum available, the standard is 92 RON, however, the most used type is 95 RON. In Ireland 95 RON is the only petrol type available through stations.
In Italy, 95 RON is the regular gasoline offered (verde), and most gas stations offer 98 RON as the premium type (Super/Blu Super), many Shell stations close to the cities offer also V-Power Gasoline rated at 100 RON.
This higher rating seen in Europe is an artifact of a different underlying measuring procedure. In most countries (including all of Europe and Australia) the "headline" octane that would be 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, this means that the octane in the United States will be about 4 to 5 points lower than the same fuel elsewhere: 87 octane fuel, the "regular" gasoline in the US and Canada, would be 91-92 in Europe. However most European pumps deliver 95 (RON) as "regular", equivalent to 90–91 US AKI=(R+M)/2, and deliver 98, 99 or 100 (RON) (93-94 AKI) labeled as Super Unleaded - thus regular gasoline sold in much of Europe corresponds to premium sold in the United States.
In the United Kingdom, 'regular' petrol has an octane rating of 95 RON, with 97 RON fuel being widely available as the Super Unleaded. Tesco and Shell both offer 99 RON fuel. BP is currently trialling the public selling of the super-high octane petrol BP Ultimate Unleaded 102, which as the name suggests, has an octane rating of 102 RON. Although BP Ultimate Unleaded (with an octane rating of 97 RON) and BP Ultimate Diesel are both widely available throughout the UK, BP Ultimate Unleaded 102 is (as of October 2007) only available throughout the UK in 10 filling stations, and is priced at about two and half times more than their 97 RON fuel.

Lewis Gibbs, consulting engineer and 45-year veteran at Chevron oil company. He's chairman of Technical Committee 7 on Fuels, part of the Society of Automotive Engineers (SAE) Fuels & Lubricants Council. Gibbs knows gas.

"My wife runs midgrade (89 octane) in her car, and it's a turbocharged engine" meant for 91-octane premium, he says.

Premium — gasoline having an octane rating 91 or higher — is just 12.1% of sales this year, down from 13.5% in 2002, when it was 22 cents a gallon cheaper, and well below the modern high of 20.3% in 1994, when it was 49 cents cheaper, according to industry and government data. Despite the allure of premium, once they abandon it, most motorists don't come back, the data suggest.

For every dime increase in the price, sales of premium gas drop 1%, Bob Johnson, general manager of gasoline and environmental services for the 7-Eleven chain, figures, based on data back to 1998.

The main advantage of premium-grade gas is that it allows automakers to advertise a few more horsepower by designing and tuning engines to take advantage of premium's anti-knock properties. But auto engineers generally agree that if you use regular in a premium engine, the power loss is so slight, most drivers can't tell.

"I go back and forth, and I'm hard-pressed to notice" whether there's regular or premium in the tank, says Jeff Jetter, principal chemist at Honda Research and Development Americas. He drives an Acura designed for premium.

Import brands, especially, use premium fuel to distinguish their upmarket models. Most Toyotas, for instance, are designed to run on regular or midgrade, while the automaker's Lexus luxury brand prefers premium. Same with Honda and its Acura luxury line.

"Generally, the more expensive the vehicle, the higher the expectation for performance and the more the customer is willing to pay for fuel," says Pete Haidos, head of product planning for Nissan in the USA.

Actually, the price debate is nearly worthless. At 20 cents more for premium, pumping 20 gallons of it instead of regular would cost $4 more. Annually, that's a difference of $171 for a vehicle that averages 14 miles per gallon — as some big sport-utility vehicles do — and is driven 12,000 miles a year.

Gasoline retailers and refiners like high-test because it's more profitable than regular-grade gas is. The retailer paid about 8 cents more for the premium you pay 20 cents more for — though that margin can swing wildly. Refiners make a few cents a gallon more on premium than on regular when they sell to wholesale distributors.

One thing we have to keep in mind, most all cars have knock sensors, and will retard or advance the timing to get the best power out of the fuel. The 14 doesn't have a knock sensor to protect it, so if its knocking its not going to stop. The rider is the knock sensor....

When I was on the phone today with EJ at Brock's, he told me to run 89 octane pump gas once I install the CT-Duals exhaust system and PC3 with Brock's ZX14 street map installed.

He says it will run better with that than 92 or 93 octane.

Hello Everyone

I marked 91 but in all actuality I use 93 which is always available near me....the sunoco's used to sell 94 octane but for some reason they dont stock it here in NYC anymore.

Ride Safe
Snuffy

I'm running a "streetbike class" this sunday. Everyone has to go for an hour long ride and fill up their tanks with pump gas for the race.

Mind you, this is a 13.5:1 compression, 1570cc big bore stroker with big cams.

I'm putting 87 octane in when we stop to fill up.

I use 91 and a little splash of Sunoco 110. Runs great and smells even better!

In OZ, the lowest you can buy is 91 (unleaded), 95 (premium unleaded) 98 (also sold as premium) and if your in the right place you can buy 100 octane

The sticker on my bike says the lowest Im supposed to put in her is 95, I generally run 98 octane though

OZ

EJ at Brock's Performance told me to run 89 octane pump gas once I install the CT-Dual exhaust system and PC3 with their street map. So I will. :)

* Last updated by: privateer on 6/8/2010 @ 4:06 AM *

in ireland its 95 only at the pumps.
travelling around france and spain in the last few weeks theres usually a choice of 95 or 98, i put 98 in a couple of times to see could i feel the difference and tbh, i didnt!

jafo that avatar pic is epic

i use Shell 91 or 93 whatever they have