Gasoline and Octane: Motorcycle Go-Juice

Old Gas Pumps

Petrol: Better Than Coal

“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.


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.


Now what about those pesky “Octane” numbers? Aren’t those supposed to represent the highest price it sells for?

In a word: “Nix.”

Pump Jacks

Fill er’ Up!

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.


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.


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.

40 thoughts on “Gasoline and Octane: Motorcycle Go-Juice

  • Suggestion, use Lucas fuel treatment in every tank. 1.5oz. per 5 gallons. Works in all fuels not just your bike/s.

  • Fighting the oil companies and our greedy goverment is a relentless battle, I’ve used Lucas Fuel treatment since I was 14 racing motocross and it was illegal to use then as it kicks up the HP’s I’ll use Reg. Unleaded when I can get my hands on it But , having to use Eythel as well in my Harley got to stay with three handle station to avoid the single ones that use blending valves and depending on where they blend from it can take up to 4 gallons before I get pure eythel (Hi Test) But still add my Lucas. Just an FYI for all my riding brother and sister out there.

  • yes on ducati tank soften like play doe comes off frame , flops around …what ever its made of is not good with e-85 … now i have a triumph 2002 metal tank but lined , carbs and alls well, but use fuel add. for the water seperation when sitting…even in lawn mowers, chain saw .etc …bmw has their own stuff but like all bmws cost big $$$ i try to use non eth e-85 from boat marine … in cans when i can … but on road well use what you can …i have seen lawn mower carbs rust the jets closed from water in fuel …but ?? on how long sitting …..”vinton” made fuel parts the best [ float needles-seats ] ..

  • rOy…
    your right…you can’t argue with facts….i was being sarcastic but it did come off just harsh…sorry to anyone who was offended….i do however own a 78 kz750 and have 70 grand on her…never did pay much attention to the gas because ethanol was at about every pump i filled her..and never had even a hiccup from the fuel system..same with my 71 bonny except only have 20000 or so on her…i think though that because i run them constantly year round may have something to do with it….my 07 919 is fuel injected and i ride her the most..but a sitting bike is probably much more susceptible to whats being discussed here…whoever mentioned stabilizer had the best advice….never owned a ducati though…fiberglass tank?…really?

  • JOHN …facts are facts … no air port has e-85 .. its all un-e85 .. 91oct must be for a reason ,sure it will burn but , it eats up the insides of the carbs [ rubber stuff ] that is just the facts… brakes down so water becomes one big floating blob…rusting away …just the fact ..less power btu’s then equal gas = burn more to go same speed = less mpg = less power at given rpm …plane motor stops you go down .. ice in carb you go down ..just the fact ..ducati fiber glass/plastic fuel tanks become soft so you can poke a hole in then with your finger … mounting tabs break off ,,, fact …. plastic dirt bike tanks fall off frame …fact ..

  • blah blah blah… ive owned thirty motorcycles in thirty years and run them all very hard and long on any gas available at the lowest price or on high test for those that claimed they required it….ethanol no ethanol they all ran fine and for thousands of miles…point is the gas that is available at American gas stations will not let you down or ruin any of your bike engines….dont care what is said…i have lived it for many years..i hear so much bs on these forums and just have been convinced that most of the yack yack technical shit is from wannabees who make excuses not to ride or do not ride much and wish they did so they pretend to be so into all this tech talk…ahhhhhh!!!….crap just ride and shut up….your engine will not blow up no mater what the gas is that you put in…Steve McQueen is rolling in his grave listening to all this crap…

  • Buy whatever makes you happy. The days of good fuels are gone to save the inner-city ghetto kids (tetraethyllead).

  • I’ve used Lucas fuel additive since way back. I have two Hondas GL1500, Gl1800 and one Harley Road King Police, I use it in all. Including my Expidition. All run smoother and I get better milage out of them all. Only 1.5oz per 5 gal. And inside my exhaust tips stays a lot cleaner as well. Ride Safe and Ride Often my Brothers and Sisters.

  • Hey guys, gasoline mixed with ethanol will reduce the distance you will travel on a given amount of fuel, and this in direct ratio. The unequivocal cause is that ethanol has about 2/3 of the heat energy of gasoline by weight. While it may be hard to find at 10% ethanol, resulting in a -3.4% distance per volume, at 85% ethanol, it is -28.9%. Ethanol in gasoline as a fix for energy independence is a scam. Alcohol fueled race cars use methanol. If you use methanol in your street vehicle it will not be for long – rapid fuel system component corrosion. Take the long way home.

  • The best thing I found that will counteract Ethanol is a product callet Star-Tron. All you need is 1 oz for each 5 gallons and if you are storing gas it will keep it stable for 2 years.

    It also helps reduce carbon build-up.

  • Hi again, so this cast iron 8hp 1957 Huskey engine of the Cushman that was to run on reg. in the late 50s will be ok if I put 91 to 93 octane in it? I only go up the street and back, but hope to get a easier engine start. thanks

  • 50’s high test was 95-101 reg was low 90’s 87 was mexican gas and you retarded the timeing to keep running with no power…but the rateing system was no doubt changed use the highest you can get that way no harm over gas, try marine gas non more but the scooter gets top miles per any way

  • I have an old 1957 cushman Eagle scooter. It has the 8hp engine. seems hard to start. If in that year it said to use reg. gas, what octane do I look for now?

  • just picked up 10 gal of non e-10 91 octane for $4.30 gas. 91 e-10 is $4.12 in daytona bch fl at 201 ridgewood ave and 1 block north of mason at cunningham oil co.

  • try blendzall #460 racing castor for 2 strokes mix in your 4 stroke tank at 100-1 comes out as 1 oz to 1 gal gas this will free up petcocks/ taps seals. e-10 dry so rubber and carb slides not happy this frees them up and castor smell right on. add more for more acts as upper lube. ok now try marine out board gas no e-10 there reg gas unleaded. to all who voted for change e-15 a comeing.

  • It certainlt seems a mixed bag of Octane ratings to deal with if I decide ride anywhere other than Australia. So, I’m going to add our mix into this topic. To state one thing up front is that I do not know how the octane rating is calculated at all and will just give figures for the Great Southern Land.

    Australian Government has legislated a maximum of 10 Percent Ethonal/Unleaded fuel mix. Also Car/Bike companies will void warranty if Ethanol mix is greater than 10 percent and would prefer you don’t use it.

    Unleaded 91 RON, our standard and lowest grade.

    Shell “E10” or equivalent from other branded fuels, Unleaded 91 RON with 10 Percent Ethanol giving a 94 RON which often sells at same price as Unleaded 91 which two brands have phased or phasing out.

    Premium Unleaded 95 RON as some bikes and cars need it.

    Shell sells “V Power”, 98 RON at some stations which I think must be for some the European based cars.

    I’m lucky with my bike, being a 1999 Honda ST 1100ABS as it takes unleaded 91 RON but will run okay on E10 if the unleaded fuel isn’t available. I haven’t noticed any lack/gain in performance and I don’t use the E10 fuel often enough to notice the difference in range from any given tank of fuel which has averaged 17 kilometers a litre over the 5 years I’ve had it. That includes daily commuting, two-up rides, and my towing trailer.

  • I can’t find non-ethanol gas here. I’m stuck and it makes me mad. You are forced to take what you can get and the gas company doesn’t care about anything but the money.

  • While I haven’t run ethanol in the bike (didn’t want to hurt “baby”) I have run three different tests in my 2009 Chevy HHR and the results were really disappointing. On regular 97 grade octane I got 30.6 MPG city and a tad more highway. With the ethanol got less than 26 MPG. And the cost of ethanol was only 5-10 cents cheaper than regular, so any savings at the pump were offset by the loss in mileage.

    My conclusion? Don’t switch to ethanol until the industry figures out how to get more miles out of a gallon.

  • Ethanol burns cleaner and cooler than gas it’s 188 proof alcohol to run it in some flex fuel trucks the carbs need to be set up for it or you will get crappie milage and no power .I have a 1995 1100 ace I use 50% ethanol and50% regular fule I get way more power and about 30mile more on a tank..

  • @Dee, in addition to owning a Honda VTX 1300 Custom (cruiser, love my bike!), I also own a 2008 Jeep Grand Cherokee FlexFuel.

    One of the major oil companies just opened a gas station near where I live that sells ethanol. I tried it for three full tanks, to see what it would do for performance and fuel economy. The results were DISASTROUS!!! I went from 17.5 MPG (city driving) using gas to about 13.2 MPG, and I experienced a NOTICEABLE drop in power, especially when climbing hills or when I had a heavier load (more passengers + cargo).

    I will never buy ethanol again, and I would NEVER use it in my bike. I think ethanol would do more harm than good to your motorcycle engine, because the octane requirements are greater than most cars. In fact, unless your car or truck is certified for FlexFuel, you should never use ethanol anyway…your car won’t be able to process it correctly.

  • Would like to hear more about ethanol content in gas. Does it eat rubber?? Does it hurt mileage / performance??

  • Modern cars and motorcycles adjust their timing to eleminate knock. Most cars and motorcycles these days will not knock on regular gas. However by tuning themselves for the lower octane, they loose preformance and therefore gas milage. In a lot of cases, the savings in cost per gallon is not realized in cost per mile.

  • Switched to a newer ride, a 2008 Kawasaki Concours, and coming from the old Concours, its night vs. day! Now I must use 91 octane and in California thats not great. I have to stick with Mobil, Chevron, 76 labels as the no-name or ARCO brands just don’t deliver the juice. To further help with the octane, I use Blendzall 385. Say what you want about additives, but in my machine it does change the engine’ behavior. Idle is very smooth, engine is slightly quieter, power is very noticeable in the 7K & up range. It also acts as a fuel stabilizer. The engine is cooler as its burning more efficiently and a unique exhaust scent too! Expensive, I recommend you try the quart size to see if you like it. Then purchase by the gallon. I use it at every 3rd/4th fill up. It’s an additive so a gallon goes a long way.

  • Power comes from centane, antiknock from octane, so octane ratings are just part of the picture

  • Ethanol
    One GGE, Gasoline gallon equivalent (GGE), of ethanol is 1.5 gallons. This volume of ethanol has the same energy content as one US gallon of gasoline. This is because a gallon of ethanol has a lower heat value or energy content (76,100 BTU) when compared to a gallon of gasoline (114,100 BTU). You FOOLS are letting the tree huggers suck you dry. Save the EARTH….SAVE THE EARTH!!!!!

  • I run my 07 Royal Star Venture and 99 GMC Yukon on 87 octane. No knocks from either. I use Startron stabilizer every couple of tankfuls.

  • My home is in California…running a BMW R1200RT Chevron 91 octane with 10% ethanol at near sea-level…in this environment on long non-stop coastal rides (Highway 1) I average 42 mpg. Compare with my annual rides up through Ketchum Idaho and Kalispell Montana where I can purchase 95-96 Octane ethanol free at Sinclair Stations…the elevation is 4K above sea level. The BMW humms along at 90-95 MPH averaging 48 MPG. Fact!!

  • I use fuel grade 95 on my 2009 Electra, however the engine still knocks when hot.
    Any recommendations??

  • Well here is my take on Higher Octane Fuel for All of my vehicles. What you need to realize is that not only does Premium Grade Fuel come with a Higher Octane Rating, it also has additional Fuel Conditioners and Cleaners not included in the lower Grades of Gasoline, to me it is like paying a few cents per gallon as Maintenenance for your Fuel System and Valves. The key to keeping a vehicle Dependable is Keeping it’s Engine and Drivetrain Clean, Premium Grade Fuel will take you a long way to keeping your Fuel and Valve Train Clean. I have been using Premium Grade fuel all my life and have very little if Any history of Mechanical Engine Failure. This would be a reason I would recommend everyone use Premium Grade Fuel.

  • 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.

Leave a Reply

Your email address will not be published. Required fields are marked *