GStwin.com GS500 Message Forum

I assume unleaded right?

A stock GS runs very well on the regular stuff.  If you have a modification like an ignition advancer, higher grade fuel may be in order.  The GS is an older-type engine, so it's not pushed to its limits in regards to combustion.

The unleaded with the shortest queue unless you like hanging out on Shell's or whoever's forecourt.

Steer clear of optimax - I found the bike was slow to warm and sluggish off the line with optimax. Pretty much any normal unleaded or premium unleaded seems fine, I don't find the performance difference much worth it for the price difference with premium though.  
You sydneysiders don't get subsidised fuel though, so it might be ok for you...

What the f.ck is Petrol?  I've personally been putting Gas in my bike!

:lol:  :lol:  :lol:

When I was riding back to Canberra from Melbourne I fed my '91 with BP Ultimate (98 octane) and it made him VERY happy - a whole lot more get-up-and-go than usual. I stear clear of Regular if I can at all avoid it because I find that I get a rougher ride.

What is the story with Optimax? I've heard from 5 different directions that it's a no-go, but no one has a reason why. I've never had any problems, although I usually go for Caltex's Vortex if Ultimate's not available. Any idea on that?

R.

er, ummm, petrol is gas, that side of the pond anyway :mrgreen:  :mrgreen:  :mrgreen: hmmmm, i thought you put diesel in it :nana:  :nana:  :mrgreen:  :dunno:

Interesting trans-Pacific language fact:

In the Wonderful Land of Aus, we refer to "gas" when we're talking about "LPG" - Liquid Petroleum Gas. Great for running you BBQ, stove or hot water system, or your car if you feel like blowing a couple thousand on the mod.

"Petrol" as in short for Petroleum.

I forget what the difference between Petrol and Diesel is...

R.

I know a guy who put diesel in his SV...bad, very bad.

OK, this is a hijack but .. I know a guy who put deisel in an SV too.  I guess it made quite a smoke cloud until he ran out of gas in the float bowls.

What's up with SV riders?

Quote from: South East RocketWhat the f.ck is Petrol?  I've personally been putting Gas in my bike!

:lol:  :lol:  :lol:

Who know what?  There's a whole other world outside of the states.  I'm sure you've never heard of Km/h either  :nana:

But, we looove Canada down here.  The USA without Canada makes about as much sense as a house without a roof (even IF the "roof" hasn't been doing a very good job keeping the snow off us lately).   :nana:

And, kilometers are such a fakey distance.  Give me a man-sized real mile any day.  You can keep your decameters (lol) and we'll keep our feet, thankyouverymuch.  

Like they say in Quebec, Viva La Difference!

"I forget what the difference between Petrol and Diesel is... "
From my very very limited knowledge a couple of diff. are that gas combusts w/ a spark. Diesel combusts under pressure. From a refining stand point the crude oil distilled at diff. temperatures for gasoline and diesel. Diesel being less distilled or refined I suppose.  I'm sure someone can correct/elaborate to what i've said.

-ash

Quote from: ravenWhen I was riding back to Canberra from Melbourne I fed my '91 with BP Ultimate (98 octane) and it made him VERY happy - a whole lot more get-up-and-go than usual. I stear clear of Regular if I can at all avoid it because I find that I get a rougher ride. R.

Here we go again...I thought the only reason for using a higher octane rated fuel (gas, petrol, whatever) was to avoid preignition (backfiring and/or "engine knock") in a high compression engine, which the GS is NOT.  I don't see how a carefully measured comparison (acceleration, top speed, fuel economy, dyno) could show any performance difference between regular or premium fuel in the GS.  :dunno:

Quote from: Splash

Quote from: South East RocketWhat the f.ck is Petrol?  I've personally been putting Gas in my bike!

:lol:  :lol:  :lol:

Who know what?  There's a whole other world outside of the states.  I'm sure you've never heard of Km/h either  :nana:

Damn, It's hard to be scarcastic around here.  I know what Petrol is...  I f%$king lived in England 5 yrs     !

/\---He was kidding.
Anyway, I always use 94 octane in my GS. Its gets bitchy with regular 87 octance. Sometimes I put in a can of that octane booster if its pinging,a nd that meks it happy.

Since we're on the octane topic ... I found that 94 octane required longer warm up time at start up.  If you do not warm it up enough, it bogs down when you open the throttle.  It could also be the amount of ethanol or some other stuff that accounted for it as well.  I find 89 works as well as anything and I don't get any ping or knock.  

Rob   8)

Interesting... My (limited) understanding was that it was the octane that gave you the "Bang", so bigger octane = bigger bang. I've always found (4 wheels and more recently 2) that higher octane makes for a smoother ride and better economy because there's less sh!te running through the engine, and each spark provides just a bit more power. I'm a Software Engineer by training, not a Petrochemical Engineer so I'm not as sure about the chemistry involved.

All I know is that the higher the octane I put in the better he goes!  :mrgreen:

R.

Well if the engine isnt designed to run on a higher octane chances are it wont do squat but make your money go faster. Unless your engine is pinging which it should help. If you run too high of an octane your might damage something. Plus some engines that are meant to run off a high octane will get more horsepower as in nissans 3.5 liter engine that run a higher compression(maxima, 350z, pathfinder...) compared to a 3.5 ltr engineered for a lower octane and has a lower compression resulting in less h.p. All in how its engineered to combust the fuel.

And just about optimax (I assume those of you across the pond don't get it) the denser fuel really doesn't seem to be handled well by the carbuerettor. Fuel injected bikes/cars fine, but there seems to be problems in fuel delivery via carbies.
I fed my 91 optimax for the frist couple of weeks and had many problems. Since, I've been using other premium fuels and standards from good petrol stations and she runs great!

i use 98... sometimes with Octane booster. it boosts about 10-15 octanes

With apologies to those who have heard this before, I've used 85 octane for most of my 30,000 miles.  The only times I haven't is when I've been  out of state and haven't been able to find it that low (read "cheap").

Here in Utah the pumps say they use the (R+M)/2 calculation for the octane number.  Is that the same throughout the US?

For a certain portion of the year the gas along the Wasatch Front has up to 10% ethanol mixed in.  I think it's an EPA-mandated thing because of the temperature inversions in these mountain valleys -- the pollution sometimes gathers for a week or two at a time before a good wind comes along to blow it all away.

So does the ethanol help the pollution to be blown off easier by the wind or just so that there's less pollution to begin with?

Manix - In Europe you pay more for petrol because your governments have decided they want to discourage people from using petrol :)

Quote from: RagnaRManix - In Europe you pay more for petrol because your governments have decided they want to discourage people from using petrol :)

Riiight, whatever...  :bs:

Quote from: ManixSo does the ethanol help the pollution to be blown off easier by the wind or just so that there's less pollution to begin with?

So there's less to begin with.

I haven't heard anyone use the word "gasohol" in a while, but that used to be the vernacular term for certain varieties of alcohol-mixed gasoline.  The more official adjective for our 10% ethanol brew is "oxygenated"....

Quote from: Kerry

Quote from: ManixSo does the ethanol help the pollution to be blown off easier by the wind or just so that there's less pollution to begin with?

So there's less to begin with.

I haven't heard anyone use the word "gasohol" in a while, but that used to be the vernacular term for certain varieties of alcohol-mixed gasoline.  The more official adjective for our 10% ethanol brew is "oxygenated"....

Somehow the word "gasoholic" springs to mind...  :)

87 is the lowest you can buy in Canada.
89 is MID
91 is premium

at most places.

some have ultra at 93 (shell) and 94(sunoco)

That finland gas is CRAZY!!  you need to go to the race track to get anything above 94 here.

I always put 94 in my bike when it's available.  It only costs about an exta dollar per tank.

My car needs 91, and it add $5-$7 per tank.

This side of the Pacific:

Regular: 91 octane
Premium: 95
Ultimate: 99.

Oh, and on the topic of costings/price, our average price/litre hovers between 90 and 99c (~70-76c US... not sure about Euros). Of that we're getting slugged ~45c in tax - supposedly to go towards road-improvements.

Kerry: How IS octane calculated? What's that formula you mentioned earlier?

R.

Quote from: ravenKerry: How IS octane calculated? What's that formula you mentioned earlier?

I don't know much about the subject of octane, but here is a quote from page 2 of the old "cc hp ?" thread:

Quote from: BadDSMWhen they "ask for 105 octane" they are most likely referring to the research octane number which is what they go by in Europe.
The gas that is sold in America is RON (Research Octane Number) + MON (Motor Octane Number) divided by two as is expressed on any gasoline pump that you use. These two numbers are derived by testing a gasoline's resistance to pre-ignition (knocking, pinging) in high load and low load situations.
Usually RON numbers are about 4-5 points higher than the (R=M)/2 method we use in the US which would give an effective required octane rating of 100 octane[....]

So, in the US the octane number advertised at the pumps is the average of two different measurement methods.

The posts by keyzer and gobstopper in the old thread help!!!!!!!!!!!!! confirm the above info at a fairly high level, and give a hint about RON vs MON.

For more on what the Research Octane Number or the Motor Octane Number actually measures, I can only suggest that you search the Net.

on the gas-a-hol topic...

I owned a FFV Ranger that would run on E85, which is 85:15 Ethanol:Octane (v:v).  I used gasahol for a bit until I made a realization...

using E85 reduced my emissions by 30%... good  :mrgreen:
using E85 reduced my gas mileage by 30%... bad  :x
using E85 reduced my wallet by about 50%... really bad  :o

so in the end, I basically broke even on how much crud I was pumping into the air, but I was paying about twice as much per mile for the fuel  :nono:

The catch is that your vehicle needs to be tuned somehow to compensate for the different vapor-pressure of E85.  That's why fleet vehicles use it effectively, because they can be set to run on only E85, in which case they get comparable gas mileage to octane with lower emissions.

raven:

I'm surprised your GS runs better on 98 octane but I take your word for it.  Gas is actually a mixture of things and not just one thing.  Maybe the mix of your 98 is much different than what ours is.  Actually we don't even get 98 here at the pump.  94 is the highest.  

I did find that my 89 Mazda MX-6 did run much better on 94.  If I filled up with 89 for some reason, I'd be driving along and thinking ... "what the hells wrong with my car"?

I live in Canada (near Toronto kinda)  and we pay about $0.72/liter ($.56 US).

Rob

For octane levels, and gas quality, Im pretty sure you cant compare NA gas vs Euro or Aussie gas. The octane levels may be higher, but the actual make up of the fuel can be quite differant.
I know when they started bringing the new pontiac GTO to NA, its a rebadged Holden Monaro from Australia. To make the car work here, they had to do some modifications to the engine to deal witht he differance in gas quality. Many cars are like that. Its just like euro diesel, its far differant than the diesel we get in NA. That, and the fact its so efficient, is why its so popular over there. You cant run a Eurpoean tuned car on NA diesel.

[Riiight, whatever... ]

Manix - R U kidding???? You mean to tell me that you live in Europe and have no idea that taxes are used as a means to discourage petrolium use?

Riiight, whateva dude  :bs: [/img][/quote]

For many years I always started my bikes out on regular 87 octane fuel.  As the miles built up and carbon accumulated, the octane required to prevent knocking in hot weather went to mid grade 89 and then to premium 91.  I ran my air cooled bikes on 10-40 oil in the winter and 20-50 in the summer on my 4 Hondas and then on the 97 GS.

After 5k miles on the 97, I changed to Mobil 1 15-50 full synthetic and as the miles accumulated did the same change to 89 and then 91 to prevent knocking in hot weather.  With about 70k on the clock early last year, I changed to the Delvac 15-40 truck oil while it was still cold out and and I was still running the mid range 89 octane gas as I did in the winter months.

Well I put another 10k miles on that bike running the 89 octane thru the summer months and never had a knocking problem.  Proof to me that our air cooled mc engines run cooler in the summer with as low a viscosity oil as practical.  Badly worn engines may still require the 20-50 or heavier   :) in the summer to keep oil consumption at a reasonable level.

Thought I'd point this all out to show how engine temps affect the octane requirements as much as carbon build up does.  The oil has 2 purposes, to keep the moving parts lubricated and also to help cool the engine.  The thinner oils will have a faster flow thru the engine and will carry more heat from the top of the engine to the crankcase area where the oil is cooled.

Although the Mobil 1 15-50 was terrific in reducing engine wear, the engine runs hotter on it than on the lower viscosity oils.  Could be by paying twice as much for the 10-40 Mobil 1 mc specific oil that the increased oil price would be more than offset by the lower octane gasoline requirement.  

I was real happy with the 15-40 truck oil last year and started the newer 02 GS out on it.  At $6 a gallon it is a terrific buy and is a high quility oil.  It has more of the additives that help prevent engine wear that were reduced in auto oils because of the cat converters and it has none of the friction reducers that are added to auto oils to increase milage a tad and that can be harmful to our clutches.

So, what was the final verdict on octane?  Sadly, I have only gassed up once since I bought Xena (must ride more!) and the shop where I bought her said to use the higher octane gas.  

Help?

I think the owner's manual might have something to say about it, but I'm not sure.  I just now looked it up in my Haynes manual (Clymer was silent on the subject) and it said

Fuel Grade  ........  Unleaded, minimum 91 RON (Research Octane Number)[/list:u]As others have noted, 91 RON should be equivalent to about 87 in the R+M/2 method used in the US.  (The Haynes manuals originate from the UK.)

In other words, you probably shouldn't go below 87, but you may want to try higher values over time and see if ol' Xena seems to run better that way.  :thumb:

As for me, I'm sticking with the 85 that's available in Utah.

PS - I never did answer your question from a while back.  Yes, I think Xena is a fine name for her....

Quote from: 500rider
I'm surprised your GS runs better on 98 octane but I take your word for it.  Gas is actually a mixture of things and not just one thing.  Maybe the mix of your 98 is much different than what ours is.  Actually we don't even get 98 here at the pump.  94 is the highest.  

I did find that my 89 Mazda MX-6 did run much better on 94.  If I filled up with 89 for some reason, I'd be driving along and thinking ... "what the hells wrong with my car"?
Rob

Yeah, it sounds like we're comparing apples with oranges. My '88 Telstar TX5 lurve's the Premium - the higher the octane the better. You get more power, which you can REALLY notice on the GS. Case in point, on the weekend I rode the 260km up to Sydney and back. I started on 95, and 1/2 way there topped up with 98. Suddenly I had just that much more power.

I've got the feeling that there is no "right" answer for the global question - it's just going to have to be a region-by-region thing. I think the consensus, though, is to hang around the ~91 mark unless you've tested the higher octanes to be better. I'm guessing that it's the difference in standards, ratings etc between countries that's causing the confusion.  :dunno:

R.

Quote from: ashmanIf you run too high of an octane you might damage something.

Er.......Actually that is wrong.
Unused octane is passed through the exhaust. Can you say emmissions???
(That's a bad word BTW)
Pump Gas of any octane will not damage your GS motor.

The exception is of course "racing fuels" witch have higher octane but also contain higher levels of oxygenates which call for rejetting for that specific fuel.
Oxygenates of course add more oxygen to the mix, making your motor run leaner and can cause detonation (burnt pistons or valves) in motors not rejetted. This is where high octane got it's bad rep.

While some pump gas in certain market areas may contain oxygenates (usually during winter), it is not to the level that will cause detonation in stock motorcycle engines.
Pesonally.....I would avoid all oxgenated fuel (including pump gas) in a stock motorcycle if possible.... but that may not be possible in if you live in a major US city.


.....and despite the GS's figures on paper......mine runs MUCH better on hi-test.
Put 3 gallons or more in your GS and get back to me.
If doesn't help you'll only be out of a quarter (25 US cents).