GASOLINE BY ANY OTHER NAME IS STILL GOOD OLD GO-JUICE
“Gasoline” in America. “Petrol” in Europe. “Benzine” in Scandinavia, Russia, Germany, Israel and Bulgaria. They’re all different terms for that favorite motorcycle go-juice we hose into our tank.
Except for a few electric bikes and any other alternative energy two-wheelers that may be in development, the vast majority of dirt bikes, MX bikes, cruisers, standards, sport bikes, sport tourers, luxury tourers and all other bikes drink up as much as you can give ‘em and then shortly thereafter demand some more. Some may sip the juice lightly, such as a moped. Others, like drag bikes, guzzle the stuff for a few seconds into hyper-oblivion.
HIGH-DENSITY ENERGY
So what’s up with this juice?
You probably know it’s refined from crude oil, which is famous in engineering circles for its high-energy density. In addition, because oil is easy to transport, and is relatively abundant on our planet, this combines to make it pretty popular in our little world. In fact, it’s the most vital source of energy since the mid-1950s when it surpassed coal. (How efficient would your bike be running on rocks?)
Because motorcyclists are required to share the various crude oil derivatives with cars, trucks, buses, boats, ships, airplanes and planetary industries, some countries even go to war when they get concerned about it.
Our famous go-juice starts out in its crude form slumbering within the earth’s crust for a millennium, dreaming about motorbikes of the future. Just about the time it starts to imagine that every niche permutation of a bike has been developed, the goo then gets drilled out of its long sleep to get cleaned up and put to work. First, it gets boiled and purified at a refinery. Then, a bunch of other chemicals get mixed into the juice to make our bikes happier (performance additives). Finally, it gets transported to gas stations all over the place so that you and I can show up and pump this highly refined concoction into our tanks.
DO YOU REALLY NEED HIGH OCTANE FUEL?
Now what about those pesky “Octane” numbers? Aren’t those supposed to represent the highest price it sells for?
In a word: “Nix.”
Higher octane numbers do correlate to higher prices, but of course, we haven’t seen prices at those octane levels in a long time. Really, octane ratings are simply used to represent the anti-knock performance of our go-juice. In other words, if you hear some audible pinging from your engine, that’s its way of telling you to feed it some higher-octane fuel at the next pit stop. In most cases, all you need is the recommended gas that your manufacturer designates for your bike in your owner’s manual. For most bikes, paying more for premium gas is not money well spent. Some manufacturers do “require” higher-octane gas for certain bikes, in which case you would be wise to ante up at the gas station to keep your baby smiling.
GRADES OF OCTANE
Most riders in North America will be familiar with the following common octane grades.
- 85-87: Regular
- 89-90: Mid-grade
- 91-93: Premium
And if you happen to be in Europe thinking those are some low numbers, realize that although the numbers may be different across the pond, the octane is not. There are different ways to calculate octane, and in Europe a different octane rating calculation is accepted as the standard. Bottomline: Octane ratings in Europe are displayed at the pump about 4.5-5 higher for the same octane level in North America.
FUEL STABILIZER
Regardless of what octane you use for your bike, one thing you want to be aware of is that gasoline, petrol, go-juice, or whatever you prefer to call it, does not store indefinitely. It deteriorates with age. Lighter parts of the mixture evaporate, leaving heavier parts to form deposits. This will cause gums to build up in the engine cylinders, as well as the fuel lines, which makes it harder to start the engine. Bear this in mind if you don’t ride your bike during the winter or any multi-month period. Petrol could become unusable in a few months or might become unusable after a year.
Hence, if you are planning not to ride for a few months, toss a fuel stabilizer additive into your tank. You can buy this at bike shops and auto stores. Use as directed, and run your engine to circulate the additive before storing your bike.
Perhaps in the future some other form of go-juice will be fueling our throttles. But for now, that gooey stuff slumbering in the earth’s crust is the fundamental power elixir for motorbike fun.
A motorcycle will run better on regular gas if you do not need hightest. A good way to make any motorcycle run on regular gas is to use Sonic spark plugs. You will never use any other plug once you use these plugs The performance is so much better than a regular plug.The plug brakes the gas up so it can burn more completly.
If you want to maximize the fuel that you’re using, try adding some Oxytane. It chemically balances the ionic charge of flowing gasoline. As a result you get a cleaner combustion chamber, better gas mileage and better performance. I use it in my sportbike and Harley. My customers love it ’cause it really works!
Octane is determined using 2 methods, Research and Motor. North America uses the average of the two numbers. (R+M)/2 Europe uses only the method that leaves the higher number.
One method (I think Motor) uses a massive, slow running single cylinder engine running on the test fuel. A lab tech then changes the compression ratio of the engine, raising it until knock is detected.
Octane is only the RESISTANCE TO DETONATION as compression, and cosequently heat increases
All liquid and gaseous fuels could be rated in Octane. Heptane (C-7) is the base line zero. Iso-octane is the basleline 100. Propane is 104, Tolulene (a solvent) is 121 (I think) methane, natural gas, is 110 (again, I think) Iso-butane also has an extremely high rating and is added to gasoline to rais its rating at the refinery. Alcohols have extremely high octane ratings but I don’t know what they are.
Engines running on these alternate fuels can be made more efficient (factoring total available chemical energy of course) by building them with much higher compression ratios than gasoline would permit from the beginning.
Pete, you can’t “retune” an engine for a different octane of gas. The compression ratio of an engine is what determines it’s octane requirements. Unless you change to higher compression pistons the octane requirements will not change. As mentioned in the article, the octane rating reflects the resistance to preignition or knocking or pinging (all the same thing) it is not an indication of it’s performance potential.
I’ve noticed that my bike rides much better and gets a few miles per gallon better mileage when I use high-octane gasoline. I’ve tested it a number of times. Must be tuned for it.
About Tim’s question. i am not a professional mechanic but I understand that most of the time you will not see as good of improvement in gas mileage and performance running higher octane unless the engine is tuned for it’s use. I have seen am improvement when towing my boat back in the days of carbureted engines but one clue I needed to use it was the loud spark knock I was getting with regular octane fuel under those hot weather conditions while towing.
I have a friend with a TR6 that said his mechanic returned it for Premium and he gets better cost per mile with premium now than when using regular becuase the engine is setup for it. something like a 20% increase in mileage while the difference between grades is much less than that.
Living in Europe I am most interested in the comment about octane ratings being different across the Pond. Except that I can’t be sure it means the number is higher in Europe, or viceversa … 8-(
It is most certainly worthwhile shelling out more for the right octane: I have a 1983 Laverda that spits and coughs on anything less than N.O. 98 ! The factory manual advises to run it on “premium”, i.e. “at least” 103 octane, but that was leaded fuel, and now those ratings are just a memory…
It would be more useful to know if buying the super-high-octane petrol that costs a few pence more per litre/gallon is actually worth bothering with and, if so, in what way it improves performance, eliminates knocking, or augments mileage. Nobody seems to know, as far as I can tell!
I ride a 92′ Concours that runs on regular gas. I tried higher octane but the bike idled funny….its a much better ride with regular. Occasionally I add techron gas additive and that seems to help with keeping the tank clean.
Very good advice on using stabilizer in your fuel if you are not going to be riding for a couple of months. I learned this on my snowblower and lawn mower as well as my Honda Shadow. The carb gets coated with gunk and causes a lot of problems. Adding Stabil or another fuel stabilizer is definitely worth the couple of bucks to keep your fuel system clean. Also, my Goldwing runs just fine on 87 octane, while my son has to run 93 in his Harley Soft tail to keep it from knocking.