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Hi, I have silly question. What to put in my bike, 95 regular, 98 premium or 100 race gasoline? In my previous bikes, all 4 cil japanese, I tanked 98 or 100. Thanks
 

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95 is plenty
 

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Regular around here is 89 octane, next up is like 92 and premium is 98 maybe 96. I have run 89 in my Cross Country for years. Im riding a bit more lately back and forth to work and with the heat here in Fl I have started running the mid grade more.
 
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The OP is from Serbia and Europe uses a different calculation method for Octane. What is 89 octane in the USA is around 95 in Europe - same exact fuel but called different octane numbers due to different calculation methods. I believe the USA uses the (R+M)/2 method and Europe uses something else.
 

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Hi, I have silly question. What to put in my bike, 95 regular, 98 premium or 100 race gasoline? In my previous bikes, all 4 cil japanese, I tanked 98 or 100. Thanks
I see you are in Serbia: So, the way octane ratings are calculated are probably different than the US method. The US method of octane ratings is research octane number, plus motor octane rating divided by two. I suspect in Serbia you use purely the research octane number. So here’s the difference: In the US, the formula of RON plus MON divided by two, gives and octane rating of fuel at 87 for regular, 89 for mid grade and 93 for Premium. However, the ratings also differ from state to state. The comparison numbers for using only the research octane number are about: 90 for regular, 93 for mid grade, and about 96 to 98 for premium.

So, on my Vegas 8 ball, I use US premium, which is what the manual calls for. In Serbia, if you are using only the research octane number, it would be 96 to 98. Or if you are using the same system as the US, it would be 93 octane. I hope this helps. There is no point in using any higher octane fuel than what is recommended, as it burns slower and wont do anything but degrade power a little bit. Using a lower octane than recommended, and a lot of victory owners do, isn’t recommenced. You run the risk of detonation and engine damage, if the operating temperatures are higher, the altitude is higher, or other factors. So, to be safe for all places where these bikes are operated, the manufacturer recommends the preimium fuel. I hope this rather lengthy explanation helps.

Cheers
John
 

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Higher octane fuel has no more or less power than low octane fuel. The only difference is that higher octane fuel has a higher autoignition temperature which makes it harder to ignite due to compression. You do not want premature detonation (aka preignition or pinging). I have tried low, medium, and high octane fuel. I get no premature detonation with any of them so I run the lowest octane (87 in the N. American method of measuring (R+M)/2 ). I do not often ride in really high temperatures though so if you were planning a long ride through the desert (unlikely given your location in Serbia), you might want to use higher octane for that portion of your trip.
 

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Actually a bike that is designed to run on regular will make a miniscule amount of increased power due to the lower flash point of regular 87. You can actually measure the BTU differences between regular and premium.
 

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Hmm. I;m not sure about that. Gasoline has specific qualities, regarding combustion and burning. The higher octane rating simply slows the fuel burn rate inside the cylinder, to allow a higher compression ration. A faster burning, lower octane rating gasoline has the same calorific value as a simliar quantity of high octane gas. The problem with the fast burning gas is that it’s likely to detonate at higher compression ratios, or preignite due to temps and pressures in the combustion chamber. The old trick used to be in carburetted bikes, if you ran a higher octane fuel, you had to advance the ignition timing. And vice versa if you you were using lower octane fuel. So, the higher octane gas burns slower, which is what you want, to get the optimum combustion at the optimum piston position. It’s the expansion of the burning gases that provide the power.

When we talk about faster and slower burning fuels, we are also talking about very short time intervals. fractions of seconds of difference in the buran rates of regular compared to premium.

I have the Lloyds timing wheel on my Vegas, and I have it set to plus 4 degrees of advance, as others have done most of the research and plus 4 degrees of advance appears to be enough. Victory set the timing advance from standard, to kick in at 2,500 rpm, if memory serves me correctly. They didn’t want any additional advance until that speed. However, 2,500 rpm on my bike in -6th gear, is I’m guessing around 80 mph or higher. We don’t usually cruise that fast, and with putting the timing wheel in, and giving a mechanical timing advance of 4 degrees, we get the advantage at lower rpms. In fact, from take off. I suspect Victory had some conditions where the spark advance just didn’t do well, so their solution was to limit any advance until you were at higher rpms. But again, they are building the bikes for a wide range of operating conditions. Few of us might ever experience the situation where more timing advance would create a problem.
 

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Not sure if you're addressing me. I professionally drag raced for 20 years gas and alcohol engines. We knew our octane and energy output from mixing fuels. You don't have to take anything I post to change your mind. It does nothing for me. Just offered it as a suggestion.
 

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Flashpoint is not the proper term for what is being discussed here related to octane. The proper term is autoignition temperature. From Wikipedia: "The flash point of a material is the lowest liquid temperature at which, under certain standardized conditions, a liquid gives off vapors in a quantity such as to be capable of forming an ignitable vapor/air mixture." For gasoline, this is -45°F. Many laypersons use the word "flashpoint" incorrectly.

Wikipedia even goes on to say, "The flash point is sometimes confused with the autoignition temperature, the temperature that causes spontaneous ignition. For gasoline, the autoignition temperature is around 536°F but this obviously varies to some degree based on the octane rating of the specific gasoline grade. Really high octane grades of gasoline (e.g. 100 octane) are designed for use in very high compression engines and can have substantially higher autoignition temperature - say 650°F or even higher.

A fuel's octane rating is a measure of the ease or difficulty of having the fuel undergo autoignition - typically caused by compression heating in an already hot engine.

There is no relationship between autoignition temperature (i.e. octane) and the amount of power a fuel generates when it is combusted. A fuel can have a low autoignition temperature and be high in power generation. Another fuel could be high in autoignition temperature and have a low power generation. Octane measures only the autoignition temperature of various grades of gasolines and is unrelated to the power generated from these.
 

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Sorry to have upset you but it is hard to trust or believe someone has significant information about a technical/scientific topic when they misuse fundamental words that are germane to the topic (e.g. "flashpoint" instead of "autoignition temperature").
 

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Quite the contrary. I realize how little the average joe knows about fuel and oil.
 

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Not sure if you're addressing me. I professionally drag raced for 20 years gas and alcohol engines. We knew our octane and energy output from mixing fuels. You don't have to take anything I post to change your mind. It does nothing for me. Just offered it as a suggestion.
Hi Sorry. I didn’t mean to upset you. However, I will say that I worked for an oil company for many years, as well as working in aviation. We learned the properties of fuels etc in both jobs. I”m only sharing what I learned many years ago.
I’m an old bastard now, so who knows?
Cheers
John
 

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Hi Sorry. I didn’t mean to upset you. However, I will say that I worked for an oil company for many years, as well as working in aviation. We learned the properties of fuels etc in both jobs. I”m only sharing what I learned many years ago.
I’m an old bastard now, so who knows?
Cheers
John
Not upset at all (y) Just sharing my racing experience with fuels. I'm an old bastard too. Welcome to the club.
 

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Not upset at all (y) Just sharing my racing experience with fuels. I'm an old bastard too. Welcome to the club.
Well, you know us dinosaurs need to stick together. I spent a lot of time working on Radial engines even as well as jets and turbo props, corporate aircraft etc. I”m a jack of all trades, master of none. You racing guys had the best of all worlds as far as knowing what works best for your engines, as you could “feel“ the results. On the theoretical side, sometimes the math and the chemistry doesn’t actually match up with the physical results. Plus of course, the type of engine etc, makes a huge difference.

We used to have dual rating aviation fuels, 100/130 130/145 etc. The two ratings were for rich and lean mixtures. However, when they stopped making anything higher than 100 low lead, which wasn’t exactly any lower lead than what was in the 100/130, we had major issues with the smaller engines that were made to run on 80/87. The plugs would foul with lead very quickly. There are supplemental type certificates a person can get to legally run auto gas in small planes, but the problem is the vapor pressure of aviation fuel is different to auto gas. Not a problem as long as you don’t fly at too high and altitude, but that’s not always possible when you are flying.

Anyway, back to bikes: I run non ethanol in my bikes in the winter, to try and keep the ethanol from jelling inside the carbs and tanks. I also use that stabil 360 additive. I’ve cleaned out a bunch of carbs with the residue from ethanol in them and it’s a a tough job. Carburettor cleaner that you dip parts in, like the old methylene chloride stuff is the only thing I’ve found that will shift the white powdery residue that blocks stuff up.

Cheers
John
 
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