For those that advocate using 87 octane in these bikes

[themess]

The worst culprit is ethanol. It replaces fuel. to get the proper a/f ratios much more is needed with alcohol. Unless it was jetted and/or designed to run these fuels, it is running lean. it has a very poor shelf life and because it has sugars in it can lead to more rapid carbon build up.

Ethanol is a fuel, with less energy per gallon. Also, the petroleum feedstocks used in gasoline have almost no oxygen in them. Ethanol has oxygen, so it needs a bit less oxygen to burn.

Ethanol has no sugars in it. ADM spends a lot of money to be sure that its processes convert all the sugars into ethanol. Anything not converted reduces their profits.

Ethanol also has a very long shelf life, as in thousands of years.

[boingk]

^ What he said.

Two strokes usually had low compression ratios around 7 to 1, so high octane fuel was not needed.

Sure, 7 to 1.

But they also have the supercharging effect of their expansion pipes, giving a much higher effective compression ratio. My little Aprilia RS125 wouldn't have been able to squeeze 33hp out of 125cc with just its 7:1 standard ratio alone... and yes it needed proper 98 octane. Fellow who I sold it to demanded that it use 95 octane because it said so in the manual - he has rebuild it three times since then I believe.

- boingk

[Dougbo]

This thread seems not wanting to die.Maybe it should. 87 octane has worked in all my bikes, whether Goldwings or Susuki GS's. Maybe it's time to move on to some other thread like oil, or tires !

[81suzi]

+1 I agree with the last

[JEEPRUSTY]

Oh yes please do.

[blowerbike]

i run 93 and on chilly days i cut it with 100 octane to stop the slight rattle under a load.

[trippivot]

I do not like gasohol

Ethanol also has a very long shelf life, as in thousands of years.

I disagree with this statement. and I'd like to add my opinion to low octane gas.

most of us do not purchase and store our gasoline in a science lab vacuum.

ANY alcohol exposed to air --- ethanol methanol whatever!, evaporates and is hydroscopic . Varnish and water concentrate in the tank after just a few days with American ethanol infused gasoline. -and- I mean the one at the gas station not just your bike.

87 or cheap gas is purchased more often by everybody and is more than likely it is fresher than that so called hi-test that has been sitting in the ground for 2 weeks.

so buy what you like, but what I am saying is when it comes to gasohol .... fresher is better.. it has the shelf life of a loaf of bread on the counter.

[GelandeStrasse]

I used the suck it and see method.
Lower octane pings if I lug it, higher octane doesn't ping if I lug it.
No idea why this is but "it is" so I use higher octane.
Maybe it's a Canuck thing?

I like this thread

[tkent02]

I used the suck it and see method.
Lower octane pings if I lug it, higher octane doesn't ping if I lug it.
No idea why this is but "it is" so I use higher octane.
Maybe it's a Canuck thing?

I like this thread

Not sure why, but a lot of the GKs do this, some ping no matter what you do.

Anyone know why?

[GelandeStrasse]

Larger pistons maybe? Or more likely to get lugged due to extra weight and riding style of average touring type personality? No idea!

[LarryJ]

I use 93. My GK still pings a little if I get stuck in stop & go traffic. Idling around in traffic heats up the combustion chambers & gets it to detonating 2500-5000, under moderate load. As soon as I get out of traffic, the head temp drops & the pinging goes away. Less octane just gets it pinging sooner & longer.

[tkent02]

Larger pistons maybe? Or more likely to get lugged due to extra weight and riding style of average touring type personality? No idea!

No, I've ridden a few that pinged even wound out with light throttle, just constant pinging, for years and years. As soon as it warms up it starts pinging. I wanted to take one apart to see what's going on inside, the owner didn't want to as it is still running. I guess they really are stout engines.

[Spot1000Kat]

For us guys down under , now that only unleaded is available at all pumps, it is preferred on pre-86 motors to use premium unleaded (approx 97 octane) , and lead additive to replace the lead which was in the good old "Super".

It took a bit for me to read the plugs correctly too , as they burn differently with this fuel.


Cheers spot

[Steve]

For us guys down under , now that only unleaded is available at all pumps, it is preferred on pre-86 motors to use premium unleaded (approx 97 octane) , and lead additive to replace the lead which was in the good old "Super".

It took a bit for me to read the plugs correctly too , as they burn differently with this fuel.


Cheers spot

Also remember that your octane rating is a bit different than ours.

There are two methods of detrmining "octane". You use the higher number, we use the average of the two numbers, which is several points lower.

Your 97 octane is probably about the same as our 93.

Oh, and we have had nothing but unleaded for over 30 years now, so welcome to the bandwagon.

.

[tkent02]

For us guys down under , now that only unleaded is available at all pumps, it is preferred on pre-86 motors to use premium unleaded (approx 97 octane) , and lead additive to replace the lead which was in the good old "Super".

If you are talking about a GS engine, they don't care about lead or lack of lead at all. I guess Suzuki knew the future was coming and planned ahead.
I don't think you need any premium fuel either, but I don't know your Aussie fuel grades.