What fuel?

[SMOKEU]

What octane fuel do you guys use in your 250s?

[Buckets4Me]

What octane fuel do you guys use in your 250s?

91 for my 1990 zxr250

[psycho22]

I always used 95 or 98 in my old Hyo and SR250

[qwertydog]

Same as the year of me bike (manufacturers specs :yes:)

[Gibbo89]

always 95 or 98. what do you use smoke?

[EJK]

I put diesel.

[davebullet]

91 in the VTR250 (all it requires according to the manual). Runs fine and we get 30km/litre.

[Lurch]

It's hard to find concensus on this but I doubt that many stock 250's would run better on 95/98 than they do on 91. Higher octane fuels do not automatically give an engine more power, they actually just burn longer and later in the compression cycle which may not suit many smaller capacity engines.

Also higher octane fuels tend to include more additives and cleaners which most of the time you are better off without and especially if your engine isn't completely combusting the fuel due to it not being tuned for it.

Partial reference:
http://homepages.slingshot.co.nz/~shanetp/FAQ.html#Question_18

[SMOKEU]

always 95 or 98. what do you use smoke?

98. I've recently started to use 91 to see if it makes any difference, but it doesn't seem to. I hope it won't detonate on 91.

[Spuds1234]

Check your manual out to see what your compression ratio is and then base your fuel purchases off that.

Easy.

[SMOKEU]

Check your manual out to see what your compression ratio is and then base your fuel purchases off that.

Easy.

11:1, I don't have a manual for it.

[GOONR]

91 in the Bandit, it doesn't like anything else.

[aprilia_RS250]

It says nothing below 95 on mine... That's all. I assume I could chuck av gas in there?:scooter:

[SMOKEU]

I checked the workshop manual for my bike, and the the fuel type just says "Petrol". I never would have guessed...

[neels]

GSXR250 manual specifies 90 or greater, comp ratio (once upon a time was) 12.5:1

[davebullet]

It's hard to find concensus on this but I doubt that many stock 250's would run better on 95/98 than they do on 91. Higher octane fuels do not automatically give an engine more power, they actually just burn longer and later in the compression cycle which may not suit many smaller capacity engines.

Also higher octane fuels tend to include more additives and cleaners which most of the time you are better off without and especially if your engine isn't completely combusting the fuel due to it not being tuned for it.

Partial reference:
http://homepages.slingshot.co.nz/~shanetp/FAQ.html#Question_18

I thought the higher the octane rating, the more resistant the fuel to pre-ignition - nothing to do with burning longer. Therefore it would make sense that engines running high compression ratios are likely to need higher octane fuel - to minimise the chance of compression induced ignition.

In other words the burn rate is the same for both fuels.

[Spuds1234]

Generally the higher the compression rating, the higher the octane rating you would use.

Have a gander at this link for more info.

http://www.faqs.org/faqs/autos/gasoline-faq/part3/section-1.html

[SMOKEU]

There are different octane ratings as well. I've heard that American 91 octane (for example) isn't the same as NZ 91 octane, as there are different octane scales. Correct me if I'm wrong.

[neels]

There are different octane ratings as well. I've heard that American 91 octane (for example) isn't the same as NZ 91 octane, as there are different octane scales. Correct me if I'm wrong.
You are right, but most specify the RON (Research Octane Number) rating which is what is used at the local servo.

[slofox]

Basically, yes, higher compression ratio needs higher octane.

BUT:

Compression ratio on its own isn't the whole story on detonation. The degree of turbulence in the combustion chamber is one other factor - which is why "squish" heads were invented once upon a time. So gas flow patterns, head design and combustion chamber shape all come into it as well...I once had a pretty cool techie book on intake and exhaust design...wonder what happened to that? I bet some fucker borrowed it and "forgot" to return it...

[ola_bitchola1]

I allways use 95 or higher in my 2 smoker not sure why just allways ran my cars on 95 or better my race car loves 98 so much it can consume a whole tank in 350ks

[AllanB]

Maybe phone Casbolts and or Hamptons - they should be able to look it up for you.

Be 91 or 95 - F-all specifies 98.

If the 91 preformed well and there was no audible pinking I'd say all good.

[SMOKEU]

I allways use 95 or higher in my 2 smoker not sure why just allways ran my cars on 95 or better my race car loves 98 so much it can consume a whole tank in 350ks

How big is the tank?

[Phreak]

I've tried 91, 95 and 98 in my CBR, doesn't like 98 much, and gets better mileage on 95 than 91... So I fill up with 95 every time now.

[ola_bitchola1]

How big is the tank?

45L its only 1.6L motor

[SMOKEU]

45L its only 1.6L motor

And you think that's bad, my 2L car drinks 40L of fuel in 250km without even going over half throttle.

[JMemonic]

Out of interest did you know formula one race rules require that the cars run on maximum RON 91 and it has to be pump gas with no additional additives. Your bog standard bikes are most likely only needing 91 if you are really keen on demonstration any improvement gained on you bike from altering the fuels book some dyno time, run the bike on 91, 95 and 98 making no alterations and see how much benefit or gain you get from the higher octane.

Then you will be able save the money you spent on the dyno time by using the correct fuel and not paying up to what 15 cents a litre extra for you fuel, might take a while unless of course you want actually get out there and ride.

There is plenty of good info on the net about this subject written by some very bright minds.

[imdying]

Check your manual out to see what your compression ratio is and then base your fuel purchases off that.

Easy.Shouldn't you check the valve timing too in that case?

[Juzz976]

Older bikes with worn needles/jets may require higher RON fuel as they'll be running slightly richer than a newer bike. CV carbs are more prone to wear as the needles tend to vibrate.

My FZR runs better on 95/98 but the major thing is on cold starts it will idle better.
Different fuels have different octane ratings and additives, the RON figure is only is resistance to pre detonation not the ration of octane.

[Techno]

91 in the Bandit, it doesn't like anything else.

Really, what year is it?

I haven't tried 91 as I was told to use 95 or 98. Seems to run ok on those.

[Latte]

Out of interest did you know formula one race rules require that the cars run on maximum RON 91 and it has to be pump gas with no additional additives. Your bog standard bikes are most likely only needing 91 if you are really keen on demonstration any improvement gained on you bike from altering the fuels book some dyno time, run the bike on 91, 95 and 98 making no alterations and see how much benefit or gain you get from the higher octane.

Then you will be able save the money you spent on the dyno time by using the correct fuel and not paying up to what 15 cents a litre extra for you fuel, might take a while unless of course you want actually get out there and ride.

There is plenty of good info on the net about this subject written by some very bright minds.

+1 - if your motor is tuned to run on 91 then it may infact lose performance running a higher octane. It was my understanding to use higher octanes when using 91 would cause pinking/detonating as the higher the RON, the slower the flame front for combustion (similar effect to retarding ignition). Manufacturers would recommend a minimum ROM to help prevent detonation.

[GOONR]

Really, what year is it?

I haven't tried 91 as I was told to use 95 or 98. Seems to run ok on those.

It's a 1997. Yeah it's just not as smooth running with anything else in it, coughs and splutters a bit.

[avgas]

^^^^^^^^^^^^

[JMemonic]

+1 - if your motor is tuned to run on 91 then it may infact lose performance running a higher octane. It was my understanding to use higher octanes when using 91 would cause pinking/detonating as the higher the RON, the slower the flame front for combustion (similar effect to retarding ignition). Manufacturers would recommend a minimum ROM to help prevent detonation.

Pinking/Detonation is the other side of the equation when the octane is not high enough and the ignition of the fuel occurs before the spark fires to ignite the fuel air mix which is why some engines need the higher octane.

You are right though in your understanding, when the compressed mixture is ignited by the spark there is a controlled burn. The time that burn takes in the cylinder gives us our power, potentially if we have an octane rating that is excessively high the burn rate will be to slow, you can have a situation where the fuel is still in the process of burning as it is being pushed out of the exhaust valve which of course could damage the valve and is really a total waste of the power from the fuel.

Now if I remember my tech lessons from 20 some years ago the difference between 91 and 95 is not likely to have this occur to the full extent but you do have potential to lose power, however going from 91 to 100+ has potential for this effect to be noticeable.

Good to see someone is actually thinking about this, not that you will really educate the masses and nor should your try, oil companies have spent billions on advertising to "educate" the public that their product is the best and that higher octane means higher power from all engines, in all honesty there are very few road cars that need 98 octane and even less bikes.

[Jonno.]

Older bikes with worn needles/jets may require higher RON fuel as they'll be running slightly richer than a newer bike. CV carbs are more prone to wear as the needles tend to vibrate.

My FZR runs better on 95/98 but the major thing is on cold starts it will idle better.
Different fuels have different octane ratings and additives, the RON figure is only is resistance to pre detonation not the ration of octane.
Higher octane doesn't have less fuel in it.

Basically: if your bike says to run on 91 anything more is burning money.

Most improvements are placebos.

[Will the ninja]

I've been changing fuels for a while and here are my findings. The bike is made to run on 91. It doesn't knock and runs the best on 91 (as in it feels faster), but mileage is the worst - averaging 20-22K's per Litre.

On 98 it runs smooth as well. But it feels like it takes longer for the engine to accelerate (just very slightly). However mileage is the best - averaging 22-25K's per Litre. As I commute, that is enough to justify the extra dollars. $2.50 for 50-75 extra K's per tank is worth it I reckon.

What are peoples thoughts on Pump Station Brands?

[GSF_Lou]

This is an interesting thread. When I bought my bike the dealer said he thought it seemed to run better on force 10. Unless he has shares with gull I highly doubt he was trying to bullshit me. I know when it comes down to tuning, you are able to pull more power out of force10 than BP 98 but as the bike isnt specificaly tuned for it (to my knowledge) should I really be running it?

[Gremlin]

Depends on bike, compression etc as already said. Hornet is completely happy on 91. KTM, being a euro bike should ideally never run on less than 95, and all the tuning has been done on that. Still, she gets good consumption on 98 as well. Ethanol fuels should be treated with caution. A bike not designed to run on it can have fuel lines eaten away etc, so I avoid. Brands? Seems to vary on bike, some seem to like one more than another. I fill with a lot of shell at the moment as it seems to give good results.

[sapperj]

98 perfered, 95 if no 98 on pump

[Hiflyer]

91 cos it's the cheapest!







What are peoples thoughts on Pump Station Brands?


TBH after some quick research last year, there is sweet F.A diffrence between the various petrol station "Brands"

Caltex's fuel is "SCIENTIFICALLY PROVEN TO CLEAN YOUR ENGINE" but if you read up about it, it's a tiny difference.

Shell's fuel "TAKES YOU FURTHER", yea it does, by 2-5%, compared to the other brands.

Dunno what the fuck Gull does, they just sell it and leave it at that I guess.

I reckon the difference between suppliers is not enough to warrant only going to that particular company.




Just go to the one that put their prices up last...

[SMOKEU]

in all honesty there are very few road cars that need 98 octane and even less bikes.

I thought it would be the other way round, seeing that bikes often have higher compression ratios than NA cars.

[scumdog]

And you think that's bad, my 2L car drinks 40L of fuel in 250km without even going over half throttle.

Pah!

My Thunderbird gets only get 200km on 45 litres:shit:

Anyhooo...back on topic...my F100 NEEDS 98 octane as it's 11:1 comp.

The bikes? 95 in all of them.

[Suntoucher]

91 cos it's the cheapest!









TBH after some quick research last year, there is sweet F.A diffrence between the various petrol station "Brands"

Caltex's fuel is "SCIENTIFICALLY PROVEN TO CLEAN YOUR ENGINE" but if you read up about it, it's a tiny difference.

Shell's fuel "TAKES YOU FURTHER", yea it does, by 2-5%, compared to the other brands.

Dunno what the fuck Gull does, they just sell it and leave it at that I guess.

I reckon the difference between suppliers is not enough to warrant only going to that particular company.




Just go to the one that put their prices up last...

Gull is all Ethanol blends, up to 10%, assumedly about 5ish depending on ethanol cost at the time.

[Nzpure]

Your all assuming that what it says is actually the octane level. I have been really into performance cars, reading up bg anything that may get you a extra 5kws or extra 8th of a second and one thing that became apparent very quickly through all of the information I read through he octane rating may have been 98 at one stage but by the time it gets tob your car/bike it's more closer to 95 and so forth. So unless your bike is pinking or your running boost stick with 91. Mind you that's just my 2c's worth.

[Gremlin]

So unless your bike is pinking or your running boost stick with 91. Mind you that's just my 2c's worth.
It does depend on the compression of the motor. The sportsbikes are usually a high enough compression that they wouldn't be happy on 91. Also common for the European bikes (KTM, BMW etc) to also want a minimum of 95 RON, and would prefer 98.

[Blinkwing]

Put 98 in for the first 4 months of owning my VL250, now I just chuck in 91 ...

[Evilelmo]

hey guys i no im late to this thread but i got a 1990 CBR i find if i chuck in 95 it runs a bit rich like u can smell the gas but on 91 it runs sweet do i need to get it tuned or narr???

[sinfull]

hey guys i no im late to this thread but i got a 1990 CBR i find if i chuck in 95 it runs a bit rich like u can smell the gas but on 91 it runs sweet do i need to get it tuned or narr???

I find most bikes need a tune now and then, at least a carb ballance.
Just be wary of mobil 91 or gulls feul as it has ethanol content which can deal to seals in alot of older vehicles mobil 95 still hasn't any ethanol and BP 91 clear also .

[Evilelmo]

thanks guys ill remember not to fill up with those... one other thing how does one go about tuning the carbs??? get one of the boys at cycle tread to do them or who would be better????

[GOONR]

thanks guys ill remember not to fill up with those... one other thing how does one go about tuning the carbs??? get one of the boys at cycle tread to do them or who would be better????

I had George from Motorcycle Doctors do mine, awesome job and a keen price too.

[Newo]

I run 91 in my '88 CBR 250.

The previous owner told me that's what he always used, and the owner before him. I've never had any issues and I average 200k's plus on a tank (plus reserve).

Speaking of reserve seeing as we are on the topic of fuel. Do many of you use your reserve fuel? I've always wondered if its a good idea or not letting it just sit there only for emergency. Sounds silly worded this way, but will it go off after a while?

I think last I took my bike to the mechanic he said it could use a carb clean/balance or what ever. Havn't done it yet but probably should. Then again you never know if a mechanic just wants a few extra dollars in the bank you know?

Not being an expert on automotive engineering myself I wouldn't know better if a mechanic told me such and such needs doing.

That's something I'm working on though. I'm keen to learn everything I can about what keeps a motorcycle ticking.

[Latte]

I run 91 in my '88 CBR 250.

The previous owner told me that's what he always used, and the owner before him. I've never had any issues and I average 200k's plus on a tank (plus reserve).

Speaking of reserve seeing as we are on the topic of fuel. Do many of you use your reserve fuel? I've always wondered if its a good idea or not letting it just sit there only for emergency. Sounds silly worded this way, but will it go off after a while?

I think last I took my bike to the mechanic he said it could use a carb clean/balance or what ever. Havn't done it yet but probably should. Then again you never know if a mechanic just wants a few extra dollars in the bank you know?

Not being an expert on automotive engineering myself I wouldn't know better if a mechanic told me such and such needs doing.

That's something I'm working on though. I'm keen to learn everything I can about what keeps a motorcycle ticking.

The reserve and main feed out of the same tankk, just the reserve pickup is lower in the tank, so the fuel used when switched to reserve is the same as when it's swithced to on.

[Gremlin]

I used reserve quite often, to make sure the line/tap etc were in working condition for when you really needed it.

Just make sure that you remember you're on reserve, when you're getting amazing mileage before "reserve" aye? There ain't no second reserve :shutup:

[superman]

I run 91 in my '88 CBR 250.

The previous owner told me that's what he always used, and the owner before him. I've never had any issues and I average 200k's plus on a tank (plus reserve).

250cc's should not have worse economy than a 2 litre car or something is bloody wrong :shit:

[SMOKEU]

250cc's should not have worse economy than a 2 litre car or something is bloody wrong :shit:

Fuel tank size...

[superman]

Fuel tank size...

I was under the impression they had at least 14L tanks... which would make 200km worse than a 2 litre car.

[SMOKEU]

I was under the impression they had at least 14L tanks... which would make 200km worse than a 2 litre car.

My CBR250 drinks around 4.5L/100km. My old 2L car drank 16L/100km when driven sedately.

[superman]

My CBR250 drinks around 4.5L/100km. My old 2L car drank 16L/100km when driven sedately.

Oh I see, 4.5L/100km is over 300km per tank. Which sounds much better :yes:

[SMOKEU]

Oh I see, 4.5L/100km is over 300km per tank. Which sounds much better :yes:

I don't get anywhere near 300km per tank. It hits reserve at around 220km usually and I don't push my luck with the reserve. I normally fill up every 200ish kms.

[KiWiP]

There ain't no second reserve :shutup:

Depending on your tank shape you may be able to lean it over to get the dregs from the non tap side. Though if you have to resort to this your planning ahead is rubbish :doh:

[Newo]

Yeah, I get about 200-220 before I hit reserve, and when I fill up I can usually squeeze in just over 10L

[Autech]

95 or 98, and only ever BP or Shell V-Power.
For no other reason than the bike feels good on it :scooter:

Did a track day on Sat and still got over 20ks per litre :gob: Hyo economy FTW, now if only they could sort out their shit suspension :facepalm:

[frogfeaturesFZR]

Was told by a mechanic mate that GULL gas is a better quality, processed in Singapore.

[Autech]

Yeah Gull is good fuel, use it in my car but not the bike as the seals on the carbs MAY not like the ethenol

[racefactory]

98. I've recently started to use 91 to see if it makes any difference, but it doesn't seem to. I hope it won't detonate on 91.

No it will be fine, run it. Or you could feed the petrol companies more?

[racefactory]

My CBR250 drinks around 4.5L/100km. My old 2L car drank 16L/100km when driven sedately.

That's fucking terrible. My 06 zx6r gets 4.4l/100km on open road and I can stretch it to almost 4l/100km flat when on a constant sub 100kmh cruise. On Honda NC30's I got 3.5l/100km. Must be raping that bike of yours everywhere.

I do use some hypermiling technique though. Still, on a CBR250RR you should be getting 3l/100km on a constant steady sub 100kmh cruise. According to Honda it does 2.5l/100km at 60kmh and I have found they are not dreaming either. If you are really steady with the throttle and keep the speed down you will get really good mileage out of these bikes.

[CookMySock]

All (4) of my bikes run exactly the same regardless of what fuel I use. Fuel endurance (range) is a good 20% better on the higher octane fuels.

Two strokes seem to run better on the faster burning (lower octane) fuels.

[D3ALN]

Whatever petrol you use get bike jetted to suit. A guy a rides with runs his wr450 on half av gas half petrol. and has had jetted to suit runs mint my bike has been jetted for 91 I run 91 and can keep up. aswell as a 250 would

[SMOKEU]

That's fucking terrible. My 06 zx6r gets 4.4l/100km on open road and I can stretch it to almost 4l/100km flat when on a constant sub 100kmh cruise. On Honda NC30's I got 3.5l/100km. Must be raping that bike of yours everywhere.

I do use some hypermiling technique though. Still, on a CBR250RR you should be getting 3l/100km on a constant steady sub 100kmh cruise. According to Honda it does 2.5l/100km at 60kmh and I have found they are not dreaming either. If you are really steady with the throttle and keep the speed down you will get really good mileage out of these bikes.

There's not much point in owning any 4 cylinder CBR unless you're going to trash it a lot.

[p.dath]

What octane fuel do you guys use in your 250s?

I'd used 91 in a CBR250RR. It does not have fuel injection.

Using a higher Octane fuel will not change anything except empty your wallet faster.

[bsasuper]

I'd used 91 in a CBR250RR. It does not have fuel injection.

Using a higher Octane fuel will not change anything except empty your wallet faster.

Whats your reasoning behind having no FI?, Carbed bikes were actually very well tuned.I get around 30km's more a tank on all my bikes using 96 octane.

[p.dath]

Whats your reasoning behind having no FI?, Carbed bikes were actually very well tuned.I get around 30km's more a tank on all my bikes using 96 octane.

Bikes with fuel injection can (though not guaranteed to) have the capability to adapt to fuel of different octane. They can change when the firing is done.

Carb'd bikes are statically tuned. And most people want to know what will happen if they simply put a different octane in their tank. And if that is the only thing you do, then their is likely to be no change.

[bsasuper]

99% of bikes than run FI dont have a knock sensor,they run a "set" ignition map, so dont know what octane fuel its squirting into the cylinder,the fuel map is also "set" (hence dyno tuners make a shit load of money by telling you your bike is now running a lot better now that they have re-maped it).Even in the 90's when I was riding bikes like the ZZR1100( carbs), it ran heaps better with 96 octane fuel.

[eden]

99% of bikes than run FI dont have a knock sensor,they run a "set" ignition map, so dont know what octane fuel its squirting into the cylinder,the fuel map is also "set" (hence dyno tuners make a shit load of money by telling you your bike is now running a lot better now that they have re-maped it).Even in the 90's when I was riding bikes like the ZZR1100( carbs), it ran heaps better with 96 octane fuel.

Forgive my ignorance, i bought my bike last week, and got my licence today so still super newb.

So if i'm running a 1993 suzuki bandit 250 on 98, can i get it set to run constantly on 98 or 91 depending on what my wallet says? Or should i just play around with the different fuel types to see which one the bike likes best? I'm not too sure if chopping and changing fuel will be bad for the bike so im hesitant to try.

Just another thing too, what does it mean when your bike 'knocks'? What's actually happening when this happens, and what should i be looking/listening for?

[racefactory]

Just run that thing on 91... it's not a high compression engined designed for 98.

[racefactory]

Whatever petrol you use get bike jetted to suit. A guy a rides with runs his wr450 on half av gas half petrol. and has had jetted to suit runs mint my bike has been jetted for 91 I run 91 and can keep up. aswell as a 250 would

You can not jet a bike to take advantage of a higher octane, you can only alter the timing.

[shonofear]

i get 20-30ks more running BP 98' octane fuel and seems to stop these weird tick/click sounds when firing up the bike.
even felt more responsive through revs, even less vibrations on highway speeds (judging from feet vibrations on pegs, could be all in me head though)
but George from motorcycle doctors recommended not going near 98 for my Suzuki Bandit 250, told me a few stories of bikes carking it on highways running too high octane for older 250's.
but now that ive put 91 in, those weird tick noises have returned, sounds carby related.

[redhat]

Yeah Gull is good fuel, use it in my car but not the bike as the seals on the carbs MAY not like the ethenol
Correct, and Gull does have good fuel that is comparable to BP or Shell - but it is a bio-ethanol fuel (10%) in the 98 octane and it doesn't suit every vehicle manufacturer. We actually have pamphlets behind the counter that specify if your vehicle should run on the bio-ethanol or not. You can probably ask for the pamphlets at the Gull stations in Rotorua/Hamilton as well if anyone is curious. In my case, all Hyosung models apparently should not use it.

I fill up at BP. :shutup:

[dblancer]

I keep to the midpoint with my bike. I run 95/96. As I always do with my cars.

I can't find a sure figure on my Jade, it is highish compression of 11, but it is also quite an old 250.
A friend told me once Japan runs 100, so if its import, run as high as can, if its domestic NZ new, it will be tuned for our lower octane fuels.

As previously mentioned, I'm never sure with a carb as its going to behave the same regardless of the fuel quality

I have talked to some people which have experienced rubbish performance out of their cars running 91, but mostly direct injection engines, turbos and imports.
I had an older style Galant, a friend put 98 in it to repay me for borrowing it and it ran like a new car... seemed to be alot more get up and go at the lights...

[explode64]

I run 95 or 98 in my RGV. never been keen enought to use 91. Both my Girl friend and her sister run 91 in their CBR250RR's. they have had heeps of issues with them when they run 95 or higher.