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Premium gas for 1980 GS1000s

  • Thread starter Thread starter Grimmage
  • Start date Start date
G

Grimmage

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Can anyone tell me if the 1980 GS1000s calls for premium octane gasoline? I heard a rumor that it does. Thanks.
 
everyone i know who runs a motorcycle 1982 or older uses the highest octain gas we can get our mits on. its is just all and all better for the engine, and cheaper than more frequent engine rebuilding
 
Your compression ratio is only 9.2:1 on that engine. There is no need for higher octane gas on that engine. You only need higher octane to prevent preignition in such cases as...forced induction setups, or non-stock piston kits that increase your compression ratio.
 
Why?

It doesn't burn cleaner, it has all the same additives all it has is more resistance to ignition.

If your vehicle isn't pinking then there's no reason to use premium gas.

If it's highly tuned with high compression ratio etc fair enough but on a 30 year old bike... it's going to make no difference unless you can get it on a RR & adjust the timing to suit.

The only other occasion where it may benefit an old engine is when there is so much coke on the pistons it glows hot & causes pre-ignition that way. If that's the case you need a rebuild soon anyway.

Dan :)
 
everyone i know who runs a motorcycle 1982 or older uses the highest octain gas we can get our mits on. its is just all and all better for the engine, and cheaper than more frequent engine rebuilding

WRONG!

These motors have low compresstion. If you have to run high octane in a stock motor then you have a sick motor that needs to be looked into why it is knocking.

Just run 87 and spend the money saved on goodies for your bike.
i run 87 in my stock 78 gs1000 with no problems.
 
This keeps coming up again and again.

I've owned GS shafties since 1986, (four 850's and now my GK), for well over a quarter million miles. I have never used premium gas in any of them. I use whatever 87 octane fuel is available at the time. Locally I go to Sheetz or to a nearby convenience store with no known brand.

If your GS is stock, it should run on 87 octane. Anything else is a total waste of money. The myths abound on this subject. I totally agree with what first timer just wrote -- that if the engine is knocking, the engine needs work.

Y'all, please save your money and get regular 87 octane.
 
This keeps coming up again and again.

And I always ask about regular gas with ethanol or oxygenated gas. Thats all we got in MN. My non oxygenated, no ethanol, choice is at the farm store. Premium for recreational vehicles, small engines, snomobiles and motorcycles. I use it and get bad mileage. I got some regular gas in my truck in WI and got really good mileage.
 
if your engine is not modified internally and doesn't have a turbo stuck to it you aren't doing it any favors with high octane gasoline. properly set up, you engine probably runs worse since, as stated, it resists ignition

high compression and forced air induction systems require this because they don't want the mixture igniting sooner than the spark hits, due to the increased pressures

save your money and ride a happy bike
 
My '78 GS1000 will run off of anything. I might be imagining it, but it does seam to run better on 91-94 octane. I will run 87 if that's all I can get, but mostly I run 91. It's only a few cents more, so I don't really sweat it too much. Plus, I like how the exhaust smells with the high octane fuel. I'd run 100LL avgas if it was available at the pump and if I didn't have to worry about lead fouling the plugs.
 
I have always run premium because our local BP station has alcohol in the cheaper grades. But on a recent trip I used both 92 and 89 octane fuels, and it seems that I was getting better fuel milage on the 89 octane than the 92. It may have been the way I was riding.

Greg O.
 
Well I learned something new today. I always though I was supposted to run high test.
 
super unleaded

super unleaded

I nearly allways run my Gs1000s on super unleaded petol I now it will return
50mpg and run alot better but could it be down to the Dyna coils & ignition
better qaulity NGK plugs fitted as well Br8eix it runs smoother as well.
A m8 of mine has one with the same set as well with same result.
 
Octane rating refers to how much of the octane molecule is in the gas. Burning gasoline in the ignition process breaks the molecules of the gas and releases energy. The octane molecule is very stable and difficult to break. A high compression engine provides a little boost to the ignition process to break those octane molecular bonds. If you run high octane gas in a low compression engine you are not going to burn it completely and could be fouling the spark plugs, and/or damaging your engine. I wouldn't run anything over 89 in a stock engine with a stock ignition advance curve.
 
octanes

octanes

One small question the petrol we get over here in England is it the same qaulity as you,
get in the USA. we have had trouble with our supermarket petrol (alegedley)
so im wondering if it would make a differance.
 
My two cents on this. If your bike is in a good state of of tune. Your bike will run fine/best on 87. High octane fuel burns cooler and slower. The best way to make power is to use gas that creates the most heat that your motor was designed to use. More heat and more rapid downward pressure on the piston will result in more HP. If you motor is pinging then you need to investgate. Pinging comes from too much ign. advance, too lean on the jetting or low float levels. The needle jets have small holes that are cross drilled to allow air to mix with the fuel. The air added will atomize the fuel better and give a complete/better burn. Fuel that is not well atomized will not burn as complete and show a lean condition on a spark plug read. We all mostly run our bikes with the carbs somewhere on the needle jet. Those cross drilled holes are as important as to jetting as the size of the mains. Some pilot jets also have those crossed drilled holes for the same reason. Hopes this helps.
 
When I purchased my bike, the previous owner said he always runs nothing but high octane, and I've stuck with that as well. But now that I've had the bike a bit, I'm not happy with the way it runs. I'm not a mechanical genious, but it seems like it's getting too much fuel, or can't burn off the amount of fuel it's been given.

I get a lot of black smoke when I rev it up, and if I put my had in the smoke and rev it, it's black and wet. I'm guessing this is gas that isn't burning.

After hearing everyones testimonials on this forum, I'm going to switch to 87 and see what happens.

Peace
 
When I purchased my bike, the previous owner said he always runs nothing but high octane, and I've stuck with that as well. But now that I've had the bike a bit, I'm not happy with the way it runs. I'm not a mechanical genious, but it seems like it's getting too much fuel, or can't burn off the amount of fuel it's been given.

I get a lot of black smoke when I rev it up, and if I put my had in the smoke and rev it, it's black and wet. I'm guessing this is gas that isn't burning.

After hearing everyones testimonials on this forum, I'm going to switch to 87 and see what happens.

Peace

I do not think that changing octane ratings will fix any problem you ever have with your motorbike. Well unless you make drastic changes to the engine.

It's time for you to do some investigating. Start with a compression check.
 
Poor Man's Octane Booster that Really Works- Long Explanation

Poor Man's Octane Booster that Really Works- Long Explanation

"Appearant octane", anyway, actual octane can't be "boosted", only bought, as in aviation fuel and racegas, but "appearant" octane means it runs the same, just costs less. Used to use tetra-ethyl lead, instead.
It just so happens that ALL auto/motorcycle makers use, as a standard, 100 octane fuel when they rate fuel economy, hp, ect, that is the testing standard (which is why you never quite get the milage they advertise), and at STP, or standard temp and pressure (of outside air). I used to take my old '79 GS1000 down to the old commuter airport and buy 100 octane AvGas for mine (after running it as dry as I could.. I'd have to borrow their gas can!) and that got me a substantial increase in both power and milage (anyone who'd buy regular 87 oct is a dummy, screw dollars per gallon and miles per gallon, using super 92 octane gets you the most miles per dollar, and is the best for your engine, as well as the best bargain) but I have come up with an even better solution: MOTHBALLS. They made premium pump gas do exactly the same thing, for a lot less money. (poor man's octane booster that works)
But they have to be NAPTHELENE moth balls, there are 2 different types in nearly identical boxes. The paradi-somthingorothersomethingorother type that are the same chemical as the "big white mint" they use in men's urinals, those wont do it. Napthelene mothblalls, 1 per gallon of premium pump gas will have the EXACT same effect (raising the "appearant octane", instead of the actual octane) as 100 octane AvGas, except for the carbon fouling reduction that a motorvehicle won't show, anyway.
I have a "cabin" out in the woods, that uses a generator (the thing carbon fouls all the time, except on AvGas.. it's made to run at one rpm all the time, and at altitude, and that was the only discernable difference between aviation fuel and pumpgas+mothballs, other than cost), it ran about 4 to 4 1/2 hours on pump gas, it ran between 8 and 12 hours with a mothball in the tank.
Suffice it to say that you'll get a lot more whump, about half over better milage (tested and confirmed, normal increase) and I rebuilt a number of my engines and there was absolutely no "harm" done, in fact, they were in better shape than they should have been. The big trade-off is HEAT, your engine will run cooler... MUCH cooler. For every 10 BTU's your engine makes, 9 go out the radiator (or wherever, with an air cooled engine: gasoline is about 10% efficient as a motorfuel), so even a 2% increase in efficiancy, that is LESS heat, means 20% more thrust/milage/HP ("go"). Actually, my math said I got about a 5% increase in efficiency, or about 50% more "go", try it yourself, if you doubt it. The only drawback is that I reeked of mothballs all the time, since I carried them on my bike all the time! The other thing is that mothballs inhibit preignition or "knock", so your engine runs cooler, knocks less, gets better milage, makes more power, by using the highest possible octane 100 or better, mothballs make 100 "appearant octane". In the old days pre-historic gas had tetra-ethyl lead added as an appearant octane booster, or "anti-knock" additive, but it's rediculously poisonous, so they took it out, now all gas is still called "unleaded"
Use 1 NAPTHELENE mothball per gallon of premium pump-gas, drop them in, they'll disolve in a couple of minutes. If you have it down, and especially if you have a trap screen in the filler neck (cars), put the mothballs in FIRST, the gas going in will disolve them.
I have an AS degree in AMT (automotive technology) and I'm an ASE Master Autotech, recognized in 48 states and I have a motorvehicle repair dealers licance in one of them, I know what I'm talking about, and the usual arguments like "it'll burn up your engine" just don't hold up.. actually, your engine will run a lot cooler, and knock less, mothballs leave absolutely no deposits or residue, and any difference in deposits or carbon build up is nullified by any water cooled engine's thermostat. As for air cooled engines, well, I could idle at a red light a lot longer without getting really hot. but there was a slight drawback, it took a tiny bit longer on choke to warm it up, although not much, and I never complained about that, or really noticed it, for that matter.
If you record your milage for tax, whatever, or just know what you spend on fuel, try it yourself, expect 50% more miles per gallon, average.

If you were worried about the difference, low octane will tend to "knock" more, so the timing can't be quite as advanced. New engines with computers have a "knock" sensor, and control the timing with that among it's arsenal of sensors, a computer controlled engine CAN'T preignaite while the computer is in closed loop, that is, when it's at operating temp, however they can while they are cold, or in "closed loop", the computer's solution to "choke" until it gets to 180 degrees. The computer does nothing but flood the engine with the richest mixture until it gets to operating tempurature, the side benefiet is that if the computer fails, the car still runs, just really, really, rich. At least the early computerized cars, anyway. Taking out the thermostat would do a number on them, too. Knock is BAD, that is when the maximum pressure is reached too soon, and the piston is still coming up and hits the flamefront that should be pushing it down, bends rods and valves and all kinds of bad things, pre-computer engines tend to do it if the timing is too advanced, when you dump on a lot of throttle, in too high a gear, like passing without downshifting, when you hear a rattle or pinging sound.... that's BAD. Your older engine has surely been timed to run on lower octane unleaded gasoline, by now, and how would you know, now, if leaded regular knocked less, anyway? I think the fact that any older engines knock at all is a side effect of not running on leaded regular, or low octane gasoline.
 
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