The good ol octane discussion

[Goldenroad66]

The infamous octane discussions are running through my head as I've been researching various forums on what type of gasoline I should put into my 79 GL1000. Previous owner was EXTREMELY clear that I should only put Premium into the tank but the manual says 86 or higher, or a research octane number of 91 or higher. So I'll ask the question that has been asked many times, what type of gasoline do you put into your GL1000 and why? I live in a flat area if that has anything to do with it..
Any info would really help me cause I'll really be breaking the bank over time with 93 oct

[portugeezer]

I use 87 octane. I only buy it from Shell unless I have to. I live in the Chicago Metro area. You can't find gasoline here without ethanol. I run seafoam in my gas about once a month.

[dingdong]

I use regular grade. Whatever octane it happens to be. The bike was designed to run on regular because of the compression ratio. Anything else is probably a waste of money. I also can't tell any difference whether I use ethanol or 100% gas. I suggest that if the bike runs better with premium that there might be a problem somewhere.

[Placerville]

Agree with the above. The PO's insistence that you use premium fuel in your GL was misplaced and uninformed. Simply put, they don't need it and you'd be wasting your money if you used it. As mentioned above, an issue up much greater concern is Ethanol. If you live in an area where Ethanol is prevalent, consider using STA-BIL Marine in every tank to combat it's affects.

[foots]

My old wing isn't on the road yet, but I have always run 87 octane in all of my bikes as do my friends. I do prefer 100% gas though. I find that the 100% stuff does make my Valkyrie run a bit more smoothly.

[portugeezer]

What does ethanol do to an engine? I never hear anything about damage from it aside from on this forum. Maybe I should start using that stable marine stuff?

[WingAdmin]

What does ethanol do to an engine? I never hear anything about damage from it aside from on this forum. Maybe I should start using that stable marine stuff?

Ethanol itself doesn't do anything physically to an engine. It can cause detonation at a lower pressure than would otherwise happen with straight gasoline. It can cause rubber seals to fail, causing fuel leaks. But most importantly, it sucks moisture up out of the air and then phase separates into a water/ethanol layer, which when fed into the carbs, can cause severe damage to an engine.

Have a read through How to make your own ethanol-free gasoline for more info.

[suvcw04]

Actually, ethanol RAISES the octane number, so it makes an engine LESS likely to detonate. That is the one and only good thing about it.
It will slowly eat at rubber, plastic and aluminum. The only thing it doesn't degrade is stainless steel. Have much stainless steel in the fuel system of anything that you own?

[sfruechte]

Stick with straight gasoline and buy premium if that is the only way to avoid ethanol. Straight gasoline costs about 10% more than ethanol but it is worth it as ethanol will degrade your mileage by more than 10%. Avoid ethanol in any engine, it is a well intentioned but inferior and environmentally unsound fuel.

[buztz]

I have owned several year model Gold Wings and currently own a 2013 GL1800 and have always ran 91 octane in all my bikes. I have worked in a Honda motorcycle shop and we always recommended the use of 91 octane to all of our customers.

[harvey01]

I would urge all owners to consult their owners manual and use the gasoline recommended there. The engineers who designed the fuel system and engine know what their bike needs.

Obviously the use of gas with ethanol can be a problem but as long as you use only gas with 10% or less ethanol you bike will run fine. And as long as you are running it constantly, a tank or so a week or like on a trip when you might do 3 or 4 tanks a day all is well. But if the bike sits with ethanol gas it the gas can begin to deteriorate and start causing problems.

Motorcycle techs love the spring because a lot of folks fail to add some form of fuel stabilizer in the fall and the carbs get gummed up. Cleaning the carbs gets expensive real fast. Fuel stabilizer is much cheaper.

Normally, around the end of October, as I do a fill up I add the first stabilizer of the year and then over winter when I get the chance to take the bike out for at least a 40 minute spin(don't start unless I can ride for about 40 min) then add more stabilizer following a top off to the tank. Don't over doo the quantity of Stabilizer added. Some springs I do add some Sea Foam or Star Tron to the first couple of gas tanks.

I also have a 81 CBX and I basically keep the stabilizer level up all the time as it usually does not get the situation where I may run two tankfuls through in a day. So far I have not experienced any fuel related problems.

[HawkeyeGL1200]

Everything I've ever read tells me "regular" gas is fine for my motorcycles. I don't like ethanol in my gas, but the closest place I can buy gas without it is a 45 minute ride away.... which kind of defeats the point of buying gas there.

I have run mid grade gas a few times, and on at least one trip, it appeared I got better mileage, but it could have been me. I don't see any reason to pay for premium gas when the engine was designed to burn regular. Maybe someone can enlighten me.

[Solina Dave]

I've owned my '78 GL1000 since it was new, and I've always used regular 87 octane fuel as stipulated in the users manual. I thought that they probably knew what was best, at least at the time. I've always use Shell fuel unless it was absolutely necessary to do otherwise. I fill the tank, and add stabilizer every winter before storage. In all of those years, and over 650,000 kms. I can say that my engine performance has been, and still is, very good, although I will say that the carbs were given the gold-plated treatment at about 450,000 kms. The rings and valves were also done at about the same time, but that was simply taking advantage of the opportunity to do so, when the engine was removed for stator replacement.
Like I was saying, I feel that if regular fuel has been working fine all these years, why mess with things now?

Come on spring..............Dave

[SteveB123]

It will slowly eat at rubber, plastic and aluminum. The only thing it doesn't degrade is stainless steel. Have much stainless steel in the fuel system of anything that you own?

About the same that is in the underground tanks (FRP, or uncoated steel), underground lines (FRP, plastic, or uncoated steel), pumps (steel with aluminum risers), hoses (rubber), or dispensers (steel, aluminum, zinc, plastic).

No noticeable increase in deterioration of components.

[WingAdmin]

When a bike (particularly one that does not have a computer with knock sensors to adjust timing) that is designed for 87 fuel is run on higher octane fuel, the only thing it does is drain the owner's wallet faster.

Contrary to what the marketing division of oil companies would have you believe, higher octane fuel is not "high powered" and does not give you more engine power. In fact, the potential energy contained in high octane fuel is actually LESS than low octane fuel - so you actually get WORSE mileage and LESS power.

The only time you get better power on high octane is when your engine is designed for high octane fuel. If you put low octane fuel in this type of engine, the engine computer will detect the knocking/pre-ignition caused by the lower octane, and will retard the ignition to stop it. This lowers the power output of the engine - so in this situation, your engine will in fact make more power with higher octane fuel. However, that's only the case when your engine requires it in the first place - as is the case with high compression ratio engines.

Our bikes do not have these types of engines. Using high octane fuel in them is a waste of money.

There is one situation however where higher octane fuel is recommended: for people who are riding in high altitudes, and whose bikes have not been re-jetted for those altitudes. If you live in Denver, chances are you've had your carbs re-jetted to run properly at that altitude. If you live in Chicago, and you're taking a trip to Denver, it's worthwhile putting a tank of high-octane fuel in to burn while you're going to be riding in the mountains. This will prevent detonation and pre-ignition.

[f1xrupr]

I have a 1980 gl 1100 with a fresh rebuild (3000 miles ?). It has vary good compression. There is a brown factory tag on the bottom right tube of the frame that reads, "minimum 91 RON (research octane number). I can see a tremendous difference it low rpm performance (I believe it's referred to by most as "low rpm growl"). However, it makes good sense that using a low octane fuel in a "well broke in engine" may not seem to matter...

[SnoBrdr]

I've owned my '78 GL1000 since it was new, and I've always used regular 87 octane fuel as stipulated in the users manual. I thought that they probably knew what was best, at least at the time. I've always use Shell fuel unless it was absolutely necessary to do otherwise. I fill the tank, and add stabilizer every winter before storage. In all of those years, and over 650,000 kms. I can say that my engine performance has been, and still is, very good, although I will say that the carbs were given the gold-plated treatment at about 450,000 kms. The rings and valves were also done at about the same time, but that was simply taking advantage of the opportunity to do so, when the engine was removed for stator replacement.
Like I was saying, I feel that if regular fuel has been working fine all these years, why mess with things now?

Come on spring..............Dave

You have over 400k miles on your 78?

Is the engine all original?

Thought I was doing good at 130k miles.

[SnoBrdr]

I have a 1980 gl 1100 with a fresh rebuild (3000 miles ?). It has vary good compression. There is a brown factory tag on the bottom right tube of the frame that reads, "minimum 91 RON (research octane number). I can see a tremendous difference it low rpm performance (I believe it's referred to by most as "low rpm growl"). However, it makes good sense that using a low octane fuel in a "well broke in engine" may not seem to matter...

91 research octane = 87 pump octane.

[f1xrupr]

Yeah...that's a thought. I was reading a "Bob the oil guy octane forum", it's interesting and kinda confusing....it seems that it depends on what country you are in, and/or, fuel ingredients....???...During my rebuild, I resurfaced my heads which raised my compression ratio, and, I also lightened my pistons a few grams (I know..had to complicate things ). Lightening the pistons wasn't planned-I chipped one of the skirts, and, my pistons were vary nice, so, I improvised. Bliping the throttle on this bike is kinda like bliping a sport bike (vary responsive), and it'll smoke a tire at half~ throttle. Those modifications probably make the "personality" of this particular engine differ more than usual.....yes, but that octane rating is a "minimum", thereby indirectly implying that a higher octane rating is optional (ie in regards to uniqueness of...). I run 93 octane non-ethanol, and, it really makes a difference! Thanks.

[Solina Dave]

I've owned my '78 GL1000 since it was new, and I've always used regular 87 octane fuel as stipulated in the users manual. I thought that they probably knew what was best, at least at the time. I've always use Shell fuel unless it was absolutely necessary to do otherwise. I fill the tank, and add stabilizer every winter before storage. In all of those years, and over 650,000 kms. I can say that my engine performance has been, and still is, very good, although I will say that the carbs were given the gold-plated treatment at about 450,000 kms. The rings and valves were also done at about the same time, but that was simply taking advantage of the opportunity to do so, when the engine was removed for stator replacement.
Like I was saying, I feel that if regular fuel has been working fine all these years, why mess with things now?

Come on spring..............Dave

You have over 400k miles on your 78?

Is the engine all original?

Thought I was doing good at 130k miles.

I only ever do relatively light maintenance myself. Over the years, if it broke I fixed it, or had it fixed. I'm sure that I don't need to tell you that it's been an expensive trip. I could have probably bought a new one with the cash I've parted with, but I like the relatively primitive nature of this old relic, compared to the new ones. New ones have too much stuff on them that would get in my way.
Having said that, there has been many replacements of worn out parts such as a fuel pump, water pump, exhaust parts, gaskets, switches, calipers, and on and on. But, like I said, the carbs were done once and the engine was given a thorough going over when it was removed to do stator work, although I don't remember specifically what components were addressed. Engine work, at that level isn't for me. Just fix it so I can ride it! I ride it a lot, and I don't mind spending a few bucks taking care of it. I never ride it too hard, but I feel the machine seems to run better, if the machine is allowed to do what it was designed to do. Also, it's been doing well running on regular gas.
One last thing. I need, once again, to replace my timing belts, preferably with the best ones available. It seems that all I'm seeing is a lot of conflicting ideas in regards to profiles, part numbers, brands, a different part number on the belt to that of the number on the box, Gates, Honda OEM etc. etc. The belt that's in there now seems to have lasted well, but I'd consider buying ahead of time, rather than remove the existing belts to see what they are, and then having to purchase, and wait for delivery. Any ideas?

[SnoBrdr]

I've owned my '78 GL1000 since it was new, and I've always used regular 87 octane fuel as stipulated in the users manual. I thought that they probably knew what was best, at least at the time. I've always use Shell fuel unless it was absolutely necessary to do otherwise. I fill the tank, and add stabilizer every winter before storage. In all of those years, and over 650,000 kms. I can say that my engine performance has been, and still is, very good, although I will say that the carbs were given the gold-plated treatment at about 450,000 kms. The rings and valves were also done at about the same time, but that was simply taking advantage of the opportunity to do so, when the engine was removed for stator replacement.
Like I was saying, I feel that if regular fuel has been working fine all these years, why mess with things now?

Come on spring..............Dave

You have over 400k miles on your 78?

Is the engine all original?

Thought I was doing good at 130k miles.

I only ever do relatively light maintenance myself. Over the years, if it broke I fixed it, or had it fixed. I'm sure that I don't need to tell you that it's been an expensive trip. I could have probably bought a new one with the cash I've parted with, but I like the relatively primitive nature of this old relic, compared to the new ones. New ones have too much stuff on them that would get in my way.
Having said that, there has been many replacements of worn out parts such as a fuel pump, water pump, exhaust parts, gaskets, switches, calipers, and on and on. But, like I said, the carbs were done once and the engine was given a thorough going over when it was removed to do stator work, although I don't remember specifically what components were addressed. Engine work, at that level isn't for me. Just fix it so I can ride it! I ride it a lot, and I don't mind spending a few bucks taking care of it. I never ride it too hard, but I feel the machine seems to run better, if the machine is allowed to do what it was designed to do. Also, it's been doing well running on regular gas.
One last thing. I need, once again, to replace my timing belts, preferably with the best ones available. It seems that all I'm seeing is a lot of conflicting ideas in regards to profiles, part numbers, brands, a different part number on the belt to that of the number on the box, Gates, Honda OEM etc. etc. The belt that's in there now seems to have lasted well, but I'd consider buying ahead of time, rather than remove the existing belts to see what they are, and then having to purchase, and wait for delivery. Any ideas?

Most seem to use Gates or Napa belts as they are great quality and you can get them just about anywhere for cheap.

[T-Rat]

OK here goes........I was told that the higher the octane rating the harder the gas is to ignite! I did not believe it until I did some research....IT'S TRUE! I had a 1996 Yamaha Royal Star V4 4 Carbs and I was putting 91 octane fuel in it and thought I was doing a good thing. Then I started having performance problems, after a ride where I would just run for awhile at a steady throttle setting (example, on cruise control) then try to accelerate to pass a car it would stumble, shutter, backfire ect. I tried everything I knew to try up to and including rebuilding the carbs. To make a long story short the problem turned out to be the 93 octane fuel. What seemed to be happening was incomplete fuel burn caused by the higher octane fuel being harder to ignite so it was fouling my plugs. When a member of the Royal Star Forum suggested this, A person I found out later was a petroleum engineer, I didn't believe it until I did the research. I switched to 87 octane and the problem went away and never returned.

[f1xrupr]

Yep T-rat, you are right...the poorest fuel cost us more...go figure! It does however help prevent pre-ignition in high compression engines.

[suvcw04]

T-rat and f1xrupr, now there are THREE of us on the planet that know this. Not good, but it's a start.

[T-Rat]

Yep T-rat, you are right...the poorest fuel cost us more...go figure! It does however help prevent pre-ignition in high compression engines.

Well it's fine where it is needed but can cause a problem in a lower compression lower heat engine as I found out!