Premium gas for 1980 GS1000s

[Grimmage]

Can anyone tell me if the 1980 GS1000s calls for premium octane gasoline? I heard a rumor that it does. Thanks.

[BentRod]

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

[Suzukfan78]

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.

[salty_monk]

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

[Go Mifune]

So which octane do you use SuzukFan78?

[first timer]

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.

[Grandpa]

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.

[bonanzadave]

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.

[catfishk]

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

[Suzukfan78]

87 here...no problems, 78 GS1000.

[JATO]

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.

[Greg O.]

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.

[normGS750]

Well I learned something new today. I always though I was supposted to run high test.

[gshub]

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.

[RJ]

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.