What fuel is best?

[Petar]

Hello everybody,

since I bought my GS500 I had full tank,but now,I hit the reserve,so I need to tank up my bike.
I still have some old fuel in my bike,and I don't know which one it is.
I'm not sure should i drain old fuel and how to do it,so that explanation (if you can explain in detail,because I'm still newbie)would be great!
And last,what fuel is best for GS,I don't ride it often,so most expensive fuel is option.

I can choose between these:
EUROSUPER BS 95 CLASS PLUS
or
EUROSUPER BS 100 CLASS PLUS


Kind regards,
Petar

[Watcher]

If it's been sitting for a long while you should probably drain it, but if it's  been running on the fuel that was in there I wouldn't bother.

You can mix fuel, putting the 100 rated petrol in what was a tank of 95, for example, won't hurt anything, you'll just end up with fuel that's, like, 98, or something.


The GS doesn't need anything fancy, nor does it ask for it.  If you want to use the more expensive fuel you can, but you're honestly just wasting money.  I'd put the 95 in.

[Joolstacho]

Yes, don't be too worried, just fill the tank with the best fuel you can get, and give it a good run, taking it down to reserve.
Then next time you fill you'll know you will have mostly fresh fuel of the rating you prefer - different markets have different octane grades,
(just go for a 95 or 98 octane in my opinion).
Modern fuels tend to go stale after a while, -most of us try to keep fresh-ish fuel in our tanks. But if you're using the bike every day or every week there's no worry.

[sledge]

Your bike will run quite happily on either.
Despite being an aged and low tech engine some GS5 owners will swear blind that their bikes run better and see a performance improvement running on 98 in stock form....... However I myself am not one of them.

Try a few tanks of 95 and a few tanks of 98. If you believe you can see/feel a difference and can justify the increased cost go with the 98, it's your call 

[J_Walker]

running 95 octane [murican'] see's an improvement when you've got pinging, have run into a few GS's that do this..

[gruntle]

My UK 2004 naked K4 ran MUCH hotter on 98 octane (being ridden hard) - don't recommend, stick to 95 octane (dunno if other country specs for fuel are different?). Bike starts better and seems perkier using DPR 9EA plugs rather than the DPR 8EA plugs - cheap enough to experiment? 

[Watcher]

Bike starts better and seems perkier using DPR 9EA plugs rather than the DPR 8EA plugs - cheap enough to experiment? 

Weird, a colder plug gave you better performance?
Unless it was just a placebo from new plugs?   

[gregjet]

The motor has a round combustion chanmber and 9:1 comp ratio. Running std grade fuel will give you proper combustion unless you are in a place where the std fuel is a low quality.
Fuel grade ( octane number) give you the activation energy required to ignite the fuel. Higher number means more energy to fire it. It does NOT give you more power. You will get more power from an engine that requires a higher octane, because it has a higher performance design ( usually...you could have a crap motor with a bad or older design squish), not because the fuel you put is is more powerful.
If you are asking about fuel grades, you need to say where you are buying it. Different places have different ways of measuring the standard and have different numbers for the same fuel ( eg US 89 is the same as Australian 91)

[sledge]

If you are asking about fuel grades, you need to say where you are buying it. Different places have different ways of measuring the standard and have different numbers for the same fuel ( eg US 89 is the same as Australian 91)

Eurosuper95?
Eurosuper98?

Go on........take a guess 

[Kookas]

A quick Google says Croatia.

[Petar]

@Watcher,I got my bike in April,and PO said he wasn't ride it for some time.Since then I ride it more then 30 times.
I was told that I should fill it up with best fuel,but I wanted to hear your opinions,since this is forum made especially for GS.

@Joolstacho,I ride my GS almost every day,and sometimes I don't ride it for a few weeks.You said you most of you try to keep fuel fresh-ish,but what will happen during winter months?
I heard that there is possibility that tank can get ''rusty''and that rust can clog hoses.

@sledge,I may try with 95 first,then 98.

@gregjet,I don't need more power,I just want fuel that will be best for casual ride,so it won't be ''bad'' for engine.
Like  Kookas said,I'm from Croatia.

@Kookas,yeah,sorry i forgot to mention I'm not (unfortunately) from U.S.

EDIT:just small off topic question.
My bike (lately) runs only on ''reserve'' and  when I try to turn petcock to ''ON'' bike runs for 500ft and then it starts to slow down,lose power and finally stops.
Do you know how can I fix it,and if you do,please tell me in details,because I'm newbie when it comes to mechanic work.
Thanks!

[gruntle]

Bike starts better and seems perkier using DPR 9EA plugs rather than the DPR 8EA plugs - cheap enough to experiment? 

Weird, a colder plug gave you better performance?
Unless it was just a placebo from new plugs?   

Yup, no question. mind you, had been 9,000mls since last plug change. BUT have been thru cold winter since and absolutely no doubt whatsoever that bike started much easier in the cold (zero choke at -7°, ridden 5 days out of 7 all year round - frequently SPIRITED on a cold engine with dodgy road surface )- doesn't make sense but that's what it was like and maybe it's just what "my" bike prefers...

For The Record: 4.5 yrs since bought bike, 2 plug changes, in 23,000mls

[Watcher]

BUT have been thru cold winter since and absolutely no doubt whatsoever that bike started much easier in the cold (zero choke at -7°

If it's fueled properly this should not be possible.

[Petar]

Guys,I still need help with this:
My bike (lately) runs only on ''reserve'' and  when I try to turn petcock to ''ON'' bike runs for 500ft and then it starts to slow down,lose power and finally stops.
Do you know how can I fix it,and if you do,please tell me in details,because I'm newbie when it comes to mechanic work.
Every help is more then welcome!

[sledge]

If you are low on fuel it won't run on ON and will run on RESERVE.

The idea is that the switch to reserve tells you of the need to refuel.

Fill the tank up and see what happens..

[Petar]

If you are low on fuel it won't run on ON and will run on RESERVE.

The idea is that the switch to reserve tells you of the need to refuel.

Fill the tank up and see what happens..

Oh,I know it will not run on ''ON'' when there is a small amount of fuel.
I had this problem even with the full tank.
It think it maybe the petcock,but I don't know how to fix it,maybe it only needs cleaning?
Do you perhaps have some video,or instruction how to clean petcock,if it's faulty that is?

[Watcher]

If it will run on RES then the petcock isn't faulty.  The only thing in the petcock to go wrong is the vacuum diaphragm and that is used for both RES and ON.

Likely there is a blockage in the ON fuel line or with the screen in the fuel tap.

[sledge]

Are the pipes in the correct places on the valve?

[Petar]

@Watcher,does always running on RES hurt motorcycle?I don't care if I'll always run on RES,as long as it doesn't hurt engine.

@sledge,they seems they are in correct places.

[Watcher]

@Watcher,does always running on RES hurt motorcycle?I don't care if I'll always run on RES,as long as it doesn't hurt engine.

No, it wont hurt the bike.  It may leave you stranded when you run out of fuel unexpectedly.

But that's putting a band-aid on what may turn out to be a bigger issue.  Sort it out.