Can I change fuel to different octane?

[seoky]

Hi.

Is it bad for the engine if I run my gt250r on 95 octane from 98?

From research it depends on the compression ratio of the engine which I have no understanding of. haha
And running 98 right now may possibly be not good for power.

I have to gradually change to 95 right? (increase 95 to 98 concentration)

Thanks champs :woohoo:

[russd7]

wont hurt your bike and no you wont need to do it gradually, you should be able to run 92 octane in it as well, its not a high performance bike
we dont get 98 down here only 92 and 96 :weep:

[Danzano]

Stock compression for that bike would be 91 octane but if it can auto advance or retard the ignition then 95 is ok to 98 will work but no benefit I would say 91 unless your looking at mods but it will probably make the most off 91 as like most bikes it's tuned for the states 89octane

Sent from my HTC Desire X using Tapatalk

[The Reibz]

Put 2 stroke mix in it. Fuck it will go hard, will root the motor but ah its a Hyobag. Not even a real bike anyway

[AllanB]

Recon you are wasting your $ on 98 ..........

[ozjohnno]

A good question and the answer is NO, you cant wreck your engine moving from 98 down to 95. It might be a different story moving down to 91. This will cause your engine to knock under load and lets face it, its a 250 so you're gunna have to wring its neck to make it go anywhere quickly. In an emergency however, 91 is better than walking, you just have to be more easy with the throttle.

[ozjohnno]

A good question and the answer is NO, you cant wreck your engine moving from 98 down to 95. It might be a different story moving down to 91. if the octane is too low it will cause your engine to knock under load and lets face it, its a 250 so you're gunna have to wring its neck to make it go anywhere quickly. In an emergency however, 91 is better than walking, you just have to be more easy with the throttle.

[Ender EnZed]

You could drain the tank completely and fill it with 91 and you'd be unlikely to notice any difference. 95 will be absolutely fine.

Don't worry about it unless you've just filled the tank from near empty with diesel.

[iranana]

The higher the octane, the more compression it can withstand before ignition. Low octane fuel in a high compression engine will pre-ignite, causing engine knock. You can hear engine knock pretty clearly. As far as I understand (which isn't a hell of a lot) the only point of running high octane fuel is so that you don't blow up your high compression engine. I think high octane fuel also burns cooler than low octane, so for high stress running it keeps the engine a little cooler. I don't really see why you're running it on 98 to begin with, since the stock compression ratio probably isn't very high. I'd hazard a guess that the fuel isn't burning as efficiently as it could be you'll be getting crappy mileage from expensive fuel.

[ozjohnno]

wherever possible I run my multistrada on 98, although I have used 91 in an emergency. All you gots ta do is take it easy on the throttle. it you hear it start to knock, back orf lil bit.

[Transalper]

If this manual (link below) is correct for your bike it says to use anything 91 or higher so yes... that would include 91 being fine.
www.hyosung.com.au/downloads/manuals/GT250.pdf (http://www.hyosung.com.au/downloads/manuals/GT250.pdf)
The EFI version may be different, you didn't say what year it is (or have i missed that).

[ellipsis]

...oh cool...an opportunity to recount a story about fuel and octane levels...mid 70's when my trade was in a big down I worked for a while at Shell Oil in the area of bulk distribution...oil tankers, trucks and 44 gallon drums...an older, near retired truckdriver who did pickups of the 44 gall drums that were Shell's, had a Morri' thou...we saved, just for him, a 4 gallon tin of dregs we sucked from the avgas empties that he brought back from the airport...we also put a bit of other shit that we took from drums before they were put through the wash...like toluol, isopropyl alcohol and whatever other chem shit we had to fill his 4 gall tin...every friday arvo he would put it in his morri...it ran like a dream, the pipe was running a grey/white colour and he had been doing it for years....

[ducatilover]

A good question and the answer is NO, you cant wreck your engine moving from 98 down to 95. It might be a different story moving down to 91. if the octane is too low it will cause your engine to knock under load and lets face it, its a 250 so you're gunna have to wring its neck to make it go anywhere quickly. In an emergency however, 91 is better than walking, you just have to be more easy with the throttle.

91 won't hurt it, this isn't 1974.

[Theantidote]

contrary to all expert advice i have been running the viagra on 91 since i got her...no knocking or loss of power...despite what people keep telling me...i did read of lead memory in engine blocks and other such wifery type tales but for me she runs, runs as well as she can and i love riding her (the viagra not my wife...oh hang on that came out wrong)
:headbang:

[Mom]

Farken hell! Cheapest transport, cheapest fuel.

Easy maths.

[BMWST?]

in my experience you will get slightly better ecconomy on the higher octane fuels,probaly enough to offset the cost difference.

[nzspokes]

Stick to what the manual says. Ive read from overseas my Hornet is set to run on 87 best. So it gets 91. I keep away from Gull and Mobil 91 due to Ethanol.

My car gets much better mileage out of 98 and it works out cheaper to run it on that.

Main thing on 250 Hyobags is to not let the oil get down or they blow the bottom end.

[skippa1]

Stick to what the manual says. Ive read from overseas my Hornet is set to run on 87 best. So it gets 91. I keep away from Gull and Mobil 91 due to Ethanol.

My car gets much better mileage out of 98 and it works out cheaper to run it on that.

Main thing on 250 Hyobags is to not let the oil get down or they blow the bottom end.

Might have to get me one of those Hyobags, I could do with something to blow my bottom end

[nzspokes]

Might have to get me one of those Hyobags, I could do with something to blow my bottom end

Shame its not in a fun way then.

[EJK]

Put diesel. It's much cheaper.

[ducatilover]

Stick to what the manual says. Ive read from overseas my Hornet is set to run on 87 best. So it gets 91. I keep away from Gull and Mobil 91 due to Ethanol.

.

You may find our octane ratings are a wee bit different from overseas ones? Not sure what the figures are, but it'll be chur on 91.
My shitheap gets 98, but it needs it. Cage gets left over 98 from the rally car, not allowed the avgas from the track car but it wouldn't do anything except turn the pipe grey...

[nzspokes]

You may find our octane ratings are a wee bit different from overseas ones? Not sure what the figures are, but it'll be chur on 91.
My shitheap gets 98, but it needs it. Cage gets left over 98 from the rally car, not allowed the avgas from the track car but it wouldn't do anything except turn the pipe grey...

They run rich as shit anyway, I ran it on 98 once and it ran like poo's.

[ducatilover]

They run rich as shit anyway, I ran it on 98 once and it ran like poo's.

I've never been a fan of poo.

[Taxythingy]

91. My carby 2007 runs just fine*, idle to redline and WFO.

*excluding the rattle from the exhaust.

[strandedinnz]

Just to thrown in some pesky facts in to the conversation :)

There are different measurements of "octane", here in NZ the pumps advertise using RON, over in the US they advertise on the pump using (RON + MON)/2

So if you get a US bike and it says in the US manual it needs to run on 91 "octane", and you bring that bike over to NZ you should not put in 91, you should be putting in 95/98.

Same goes if you buy an NZ bike, go online for a user manual to find out what fuel you want .. make sure the manual is an NZ/AU print and not the US one and that it defines what "octane" they are referring too.

For all sorts of fun facts about octane ratings go to Wikipedia (http://en.wikipedia.org/wiki/Octane_rating), it explains it better than me :)

[russd7]

Just to thrown in some pesky facts in to the conversation :)

There are different measurements of "octane", here in NZ the pumps advertise using RON, over in the US they advertise on the pump using (RON + MON)/2



so im guessing we just use the lateRON method and the yanks use the lateRON method but maybe MONday :cool:

[Tigadee]

I've heard that the 91 tank at the refinery contains all the gunk from when they flush the pipelines transporting different fuels, anything from diesel to LPG?

Was shown two cylinders from two engines here, both same age: one ran on 91 and the other on 95/98. The one that ran on 91 was black and the other was only mildly coloured.

Even if the manual says you can run 91, that isn't an absolute [more of a minimum, as other countries can have lower octane fuels available, like 88) and you can still run a higher octane fuel if you wish. You may not notice a difference but the engine will!

[ellipsis]

I've heard that the 91 tank at the refinery contains all the gunk from when they flush the pipelines transporting different fuels from diesel to LPG?



...I bet the ratio of how much other stuff is allowed to 'blend' with the cheap shit fuel here hasn't changed...any residual spirits in the pipeline could be let into the lesser grade fuel...or the fuel could be dropped straight into the big holding tanks that may have had 10 to 20,000 gallons of other spirit left from prior use...the stuff that went into the lesser fuel could have been anything from turps, white spirits, kerosene, and any number of chemicals that had some kind of flash point...I've always been wary of the lesser octane stuff...