When I got my 2005 GS500F delivered the salesman said I can fill it up on any fuel I like just not Shell Optimax! (98 RON)

He said it would run better on water than Optimax.

This seems to be a common theory that many bike don't like Optimax, (my cuz's CBR250RR's plugs fouled due to a bad batch of Optimax).

Now I know that the bike only needs a 91 RON Unleaded fuel... but has anyone had any experiances with different brands or grades of fuel with the GS500?

I'm currently filling it up on BP Ultimate 98 and it is going really well.

What do you members from the land down under feed your little GS?

I use BP lowest grade here in the states whatever that is (87 or 89?)with no problems....higher octane than what the bike calls for is a waste of money IMO if it is not detonating.  You might try some JP8

I always run at least 95 ron if not 98 where possble, thats in all my petrol vehicles (I/we now have a diesel carwhich we get around 40MPG).
I have found that the optimax seems to run ok in the bike, but the choke has been sticking a little.

IMHO the higher octane fuels seem to give you slightly better fuel economy & seem to make the car/bike run a little better. But it always helps to take them for a good run quiet often to burn the crap out of them.

Yeah, I was also told by a biker friend that you need to give bike engines an occassional blast to 'clean out the cob webs'


- helps clean the plugs
- free up carbon deposits on the valves etc

I'm happy paying for the expensive fuel (knowing it probably doesn't help performance too much) in the hope I'm getting quality fuel. The last thing you want is a dodgy batch of fuel when accelerating away from a certain collision with a Mack truck.

I also see BP claims Ultimate is better for the environment and keeps your engine cleaner. If this is true I am also happy to pay a small premium.


Also, is it true the GS500 can't use ethanol blends?

I always heard that the lowest grade that doesn't detonate is the best. Any more is a waste and will foul the plugs and get carbon everywhere. (or something like that). Speaking to that, I have see the cars that say "use only 98 grade", or the best at the pump. Then I have also seen some other cars say "use only 89 grade" (usually the lowest grade)



galahs: don't all the gas companies claim their gas is the best for the enviroment/ cleans your engine the best?
RE:ethanol blends.. well it must not be, I use it in my gs500.

I had a freind's father, who worked for Shell, say that Shell puts so many additives in their gas that it'll score the jets in the carburetor, impeding flow. The GS (mine, at least) prefers Chevron/BP to all the others.

    I have been using MOBIL premium for years now in the 95 GS with MOBIL 4T oil , and it still
         goes like a scallded cat! plugs are clean ,no carbon [but the tacho cops a hideing ]
         WHEN YOUR ON A GOOD THING STICK TO IT......... like your GS !                 
             
           
                  next time !

     

the gs I ran ran fine no matter what I put in it...seemed to run best on the middle stuff, though.

It's an absolute waste of money to buy higher octane than is required to avoid pre-detonation. The fuel is all the same. One isn't cleaner than the other. "PREMIUM" is the worst marketing scam in the fuel industry. They lead you to believe that it's "cleaner" than "regular." When in actual reality, the octane rating is simply related to detonation. Higher compression engines, say for example 12:1 would require a "premium" fuel whereas say 9:1 would require "regular" or 85/87. Use the lowest octane rating that you can use to avoid pre-detonation or "pinging." Anything more and you're wasting money. It isn't any "better" for your engine and in reality you're probably screwing yourself out of some performance at the same time! How's that for kicking yourself in the ass! Check your manual to find out the compression ratio and/or what it reccomends.

I know my explanation isn't all that scientific sounding but ask anyone that's educated in fuel or someone that's worked in the industry for a while. I used to believe that "premium" meant "better fuel." Boy did I feel like a complete idiot when I decided to educate myself years later to prove the "it's all the same" guys wrong... So much money I wasted on that "better fuel."

Quote from: bubba zanetti on January 18, 2006, 04:02:23 AMIMHO the higher octane fuels seem to give you slightly better fuel economy & seem to make the car/bike run a little better. But it always helps to take them for a good run quiet often to burn the crap out of them.

This is true IF your car/bike requires permium. Premium usually does contain a slight amount of cleaning detergents, but as for the fuel itself... refer to my previous post... All the same...  I mean I get 65-70MPG on my GS using 87 octane! I could spend the extra money for 89 or 92 but I doubt I'm gonna get better than that! I get on my GS pretty hard on open roads and moderately during normal traffic acceleration. The GS is a low compression motor so it only makes sense to put a low compression fuel in it. Putting a higher compression fuel such as premium in it will only give the bike difficulties in detonating the fuel and most likely cause it to ping... However, the GS500 is known for running "hot" due to it being lean so I'd imagine if you can run premium in it without it pinging, it's most likely attributed to the fact that the additional heat is helping with the detonation.


I dunno about that last part mechanically but I make that assumption from my Mercedes requiring premium fuel and it's a low compression 4 cylinder... However, it has a supercharger on it that creates additional heat and so I have to run premium because of it. Besides, the manual says so. =P

^The part where you say "It's an absolute waste of money to buy higher octane than is required to avoid pre-detonation" is true but the rest is...ummm...vague and partial nonsense.  There's a significant difference in the quality of fuels and a lot of petrol agencies drop a lot of additives into their varieties which also ranges the differences.

And your kompressor requires a higher octane because of it's forced-induction system, which ups the compression ratio considerably.  Very few forced engines have come from the factory without a premium fuel recommendation.

the Higher Octane Fuels are to help prevent detonation in the Higher compression engines.  while there are some better additives and larger Quantity (even that is debatable) there is no power difference.   its the Engine design not the fuel (as unleaded's go anyway)

Most the bikes ive owned run well on regular, its a prefrence thing as to where i get it cause of nasty storage, Water leaching or draining into the tanks, or the stattion just has shitty filtration.   Hess fuel is no better or worse then mobil or shell,  however i have found here in south florida Hess seems to keep up on thier tanks better. Shell and cheveron's have never done well, always seem to have water. Mobil, Amaco(now BP around here) have done ok.   the only fuel i noticed a power diff was in my 82 gs750E and it was the Amaco Gold prem fuel. but that motor was worked alittle and im sure it detonated abit with regular 87 unleaded

As to Optimax.  cant say i have heard of it.  as to ethanol blends im sure it can with the correct jetting,  I think Rema is doing something of those lines now but understand its not as efficiant in Miles per Gal but may be cheaper then reg petrol.  Im not entirely sure, but i think there was somthing with useing the blends Meth, Eth etc, was it tended to dry out the seals in the fuel system pretty quickly as far as vehicle life goes. But the engines ran considerbly cooler.

Quote from: Blueknyt on January 18, 2006, 03:07:08 PM
As to Optimax.  cant say i have heard of it.  as to ethanol blends im sure it can with the correct jetting,  I think Rema is doing something of those lines now but understand its not as efficiant in Miles per Gal but may be cheaper then reg petrol.  Im not entirely sure, but i think there was somthing with useing the blends Meth, Eth etc, was it tended to dry out the seals in the fuel system pretty quickly as far as vehicle life goes. But the engines ran considerbly cooler.

Optimax is the high octane (98 ron) sold by shell in Australia. Shell have recently released a 100 ron version of Optimax, 98 Optimax with 5% Ethanol. The only thing is that you can only buy it at selected servo's in some Capital cities.

I always use bp ultimate. I have been told to stay away from optimax by everyone i have spoken to about it in the bike field.
I have never had a problem with ultimate (except ofr 6 weeks when stocks dreid up and they had to wait for it to be shipped from over seas  )
to me I notice a difference over standard fuel, but who knows maybe its a placebo effect.

It sounds like the octane rating on this Optimax is insanely high which would account for a motor not designed for such an octane to run crappy. What's so special about said Optimax? Does it contain an additive that is suppose to boost performance or is the only known fact about it that it has 98 octane? If its 98.... It's no wonder it's running crappy in your bikes. That stuff is meant for extremely high compression racing motors and I know we like to consider our little GS's as "high performance race bikes" but alas they are not and have a mere 9:1 compression (at least my 05 does) and it's a total waste to run a high octane.

Shell Optimax
What is Shell Optimax?
Shell Optimax is a High Density, High Octane premium unleaded fuel. Shell Optimax is a highly refined high performance fuel which has been refined to a minimum of 98 RON. The fuel is produced from high-octane refinery component blending streams and has been carefully formulated to produce a fuel with high octane and good volatility characteristics to ensure smooth, rapid combustion.
In addition Shell Optimax contains a high performance fuel additive that has been designed to keep the fuel system and engine inlet system clean and free from deposits. The Shell Optimax formulation is designed to clean up deposits other petrols can leave behind.

What are the main benefits of using Shell Optimax?

There are three performance features of Shell Optimax:
Improved combustion, higher volatility which can lead to greater responsiveness
Consistently high density, which may result in better mileage
Engine cleanliness. The advanced high performance additive system added to Shell Optimax is designed to ensure good fuel system clean up and maintain the cleanliness of the fuel system.

Shell 95

Shell Unleaded 95 is a new high octane brand of fuel with a minimum octane rating of 95, compared to regular unleaded with an octane rating of 91.
As part of a commitment to reduce greenhouse gases by 2009, many vehicle manufacturers are now producing vehicles that require fuels with a minimum octane rating of 95, a level that will become the base standard for all unleaded fuels.
Shell Unleaded 95 is now part of Shell's comprehensive suite of motor fuels, which includes regular Shell Unleaded Petrol (having a minimum 91 octane rating) and market favourite Shell Optimax – a 98 minimum octane fuel specially formulated to deliver superior engine power, responsiveness and cleansing benefits.

Shell Unleaded

Shell Unleaded Petrol has a minimum Research Octane Number of 91. Shell Unleaded Petrol is designed for use in all motor vehicles registered in Australia since 1st January 1986 and some pre 1986 models (refer to owners manual to confirm this application). It is also suited for all 2 and 4 stroke applications associated with motor cycles, marine, motor mowers, chain saws, brush cutters etc., which have a requirement for petrol with an octane number of 91 or less.
Shell Unleaded Petrol contains additives designed to clean deposits within the engine. A clean engine means your vehicle will be working at its optimum performance and with reduced emissions.

All major fuel brands have the 3 fuel octane ratings the same as shell.

The main reason I run 95 min in all my cars, is because they are all leaded motors & super petrol was around 94ron. Unleaded fuel only became compulsory in 1986. last year super/lead replacement fuels were phased out, so all you can get now is unleaded.

BTW I've had good results using Caltex Vortex in my cars.

Sounds like RON and our scale in the states are different but I believe they match up with our regular, plus and super. Roughly.  I seem to recall that 90 RON was equal to 86 octane here.

Quote from: john on January 18, 2006, 05:50:05 PM
Sounds like RON and our scale in the states are different but I believe they match up with our regular, plus and super. Roughly.  I seem to recall that 90 RON was equal to 86 octane here.

I believe that our rating system is the same as the Japanese & Europe.

ive seen very few ODD octanes here,   mainly we have 87 Reg,   89 plus/midgrade and 91/93 Premium/Hightest.  i remember my 68 beetle ran better with 87 with lead substitute additive, and all my camaros ran better with 89-93 save one which i ran 1/4 tank of AVGAS with every fillup and it didnt matter if it was 87 or 93 but noticed a big diff if the AVGAS wasnt there even with 93 in it.    But then it was running a smallblock 400 with flattops, mild cam, and 700 holly. never could get the stumble outa it when the secondaries opened.

They use RON we use (RON+MON)/2  Mon tends to be lower which makes our octane rating lower than the rest of the civilized world.