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Discussion Starter #1
I posted a couple posts about what octane fuel and get a mixed bag response. Well, I have been using 87 octane (American) and listened to the majority from online responses. No problems. Ride my bike daily and haven't a complaint.

http://www.cbr250.net/forum/cbr250-performance/61978-87-92-octane-my-honda.html

Today to test the water I tried 93 octane. Holy cow, what a world of difference. It's like I'm driving another bike. I'm using 92 or 93 from now on. The bike had much more noticeable power and response. It was day and night. I drove about 40-50 miles but knew after the first mile. It was great.

I can't understand how this is debatable. I even had someone respond that they thought the higher octane made their bike run sluggish. I don't get it. Unless Im missing something.
 

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Same brand of fuel? Ethanol in the 87?
I was never able to test 87 myself as it's not available anymore in Germany but I'm really surprised by your report considering the engine was developed for 87.:surprise:
 

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if you want more power and feel more power
from using slower burning petrol in your
10.7:1 compression ratio engine, then
make yourself happy..

different petrol outlets have different quality
petrols at the pump, some old or dirty or
moisture laden [esp ethanol blends],
some fresh, clean and unpolluted..
aside from octane, this could be
your experience..

many riders including members here
have used and tried different octane
with no increase in power etc..
i have used 95RON= 91PON [USA]
and 98RON = 94PON [USA] in emergencies
and to avoid ethanol in 91RON [= 86PON]
over well known regular courses, with no
increase in performance etc..

altho, cbr250r and cbr300r both ran ok on
the slower burning ie, higher octane rated petrol..

these things have been tested and examined
by experts in engine design of both four
and two wheel vehicles engines..
with normally functioning engine
and normal clean petrol, the best for
our 10.7:1 compression ratio engine
is 91RON [about 86PON] petrol..

the potential problem for everyone
is pre-ignition [bad] which can lead to
serious engine damage..
higher compression ratio engines tend to
pre-ignite their compressed fuel gas
more readily than lower cr engines,
thus need slower burning petrol..
higher octane is slower burning..
lower octane is faster burning..

for our 10.7:1 cr faster burning petrol
ie, lower octane is 'better'..
faster burning fuel gas generates
a certain flame throw and shape,
which is a design element of
all modern engines..

 

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Discussion Starter #4
I want to do some more consistent fuel usage with the same type and then switch for a little bit to make sure it's not all in my head. Another variable could be that I used a different brand of gas all together.

I swear my bike had more pep today after filling up with this gas.
 

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Like Shisoshin I tried a full tank of 98 octane in my 300R after about 2 years of running my old 250R and the 300R on 91 Octane.
I went into this experiment with a completely unbiased mind and was happy to embrace any increase in performance.
Unfortunately there wasnt one...
 

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In South Africa we only have 95 octane petrol. So that's all I can test hahaha.

I've now owned and rid the bike for over 3 years with no problem.
Maintain and look after the bike it should give you many years of joy.

Safe riding all.

Sent from my SM-N910H using Tapatalk
 

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PPP: Could it be the placebo effect? Medical studies have proven that it exists.
 

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I want to do some more consistent fuel usage with the same type and then switch for a little bit to make sure it's not all in my head. Another variable could be that I used a different brand of gas all together.

I swear my bike had more pep today after filling up with this gas.
As Schroeder asked in his post, did the 87 octane you were previously using contain ethanol?... if it did, and the gas you are using now doesn't have ethanol, then there is your answer. Ethanol blended fuels won't produce as much power as a non-ethanol fuel.

As for octane ratings, there seems to be a common misconception/urban myth that fuel with a higher octane number translates to increased performance, which is simply not true. As shisoshin wrote in his post, higher octane fuel is only needed to prevent detonation (aka pre-ignition or knock) in higher compression engines. And a fuel with too high of an octane number for a given engine can cause problems like difficult starting.
 

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Despite all evidence to the contrary, I have also noticed an added bit of "pep" in the bike when I've experimented using higher octane gas. But like Schroeder and MotoMike suggest this could very well be due only to the fact that I used premium brand-name gasoline that contained less ethanol. The biggest difference I've noticed so far was when I used Shell 93 octane and a little less so when filling up with Mobil 91 octane.
Trying the same with mid or high octane grades of "generic" gasoline sold at box store or convenience store pumps yields far less noticeable results.
I can only surmise that there is indeed a noticeable difference when using nationally-branded gasoline with less ethanol content, however I'm not sure I'd want to run it in my bike all the time given it's intended purpose of combusting slower to prevent knocking. I can't see how this would not have a deleterious effect on the CBR's engine over a long period of continual use. While I may "treat" myself and my bike to lower ethanol, higher octane fuel on occasion, I think it's always best to follow the manufacturer's recommendations at least the majority of the time.
 

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however I'm not sure I'd want to run it in my bike all the time given it's intended purpose of combusting slower to prevent knocking. I can't see how this would not have a deleterious effect on the CBR's engine over a long period of continual use. While I may "treat" myself and my bike to lower ethanol, higher octane fuel on occasion, I think it's always best to follow the manufacturer's recommendations at least the majority of the time.
You'd be surprised how many 16 year olds fill up their 125s with 93 fuel over here cause: Moar Pouwaaa!!!:grin2:
 

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didnt want to go straight to placebo effect
for causation, ie of the feeling of more power,
as expected,, but as jsonder rightly points out
placebo effect is a proven reality..

there are various shades of this reality
which extend into [false] witness identification
and other experiences based on expectation..

this is one reason why those seeking genuine info
on many different things opt for evidence based on
external sources such as dyno testing, lap times,
stopping distances and suchlike..

bottom line here tho is that these engines will
function on slower burning fuels..

last weeks petrol prices/octane; 91 - 125, 95 - 138
and 98 - 144cents per litre..
so thats 13 or 19 cents/liter extra cost
for 95 or 98 octane 'premium' [price] petrol
per litre..

im gone to yoga now but someone
with an eye on fuel economy can
work that out over the life of
the motorcycle..
 

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Discussion Starter #12
I work in the medical field. Occasionally we do studies. I watched a lady be cured of chronic knee pain and ditch her cane she had been using for some time while she was in the placebo group. Basically we shined a light on her leg and told her she would get better and she did.

I'm pleased that placebo would make my bike faster though. You guys should get some for your 250s. Haha.
 

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If you indeed really did see that increase in performance, and ethanol content is the same (it is around here between 87 and 93), and brand is the same, then you are getting pre-detonation and your bike is pulling timing on 87 to compensate. That's the only way the 93 would help your bike.
 
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its wonderful and good to feel your motorcycle
performing well.. one of the good things
in life, some would say..

thats not in question here..
it comes back to the pragmatic question
of what is best, in the sense of what works
and why.. whether a lifestyle motorcyclist
or a temporary commute only rider, this
engine has been designed to run on
91[RON] ie, 86/7[PON] petrol..

honda could easily have designed a higher
compression ratio engine, for more power,
thus needing slower burning petrol
to avoid detonation etc..

higher octane could be useful in some
situations likely to influence pre-ignition,
such as overloading/lugging engine,
eg, two up with extra loads, plus steep
uphill runs in very hot weather..

novices should not be riding two up
and/or carrying heavy loads [anyway]..
so even there it would come back to
rider skill and awareness etc..
 

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One of the key factors in deciding to buy my Honda street bike was the fact that it was designed to run on regular gasoline. The other bike that I was considering required premium fuel.

That can be a problem when you are traveling on infrequently used roads, where regular and diesel are often the only two choices.
 

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I work in the medical field. Occasionally we do studies. I watched a lady be cured of chronic knee pain and ditch her cane she had been using for some time while she was in the placebo group. Basically we shined a light on her leg and told her she would get better and she did.

I'm pleased that placebo would make my bike faster though. You guys should get some for your 250s. Haha.
I'm not buying the 'placebo effect' where internal combustion engines and fuel octane ratings are concerned, for the simple reason that motor vehicles are machines, and as such are not sentient beings. Appropriate fuel octane as it relates to a given engine's compression ratio is based on science and math, not faith and belief.

That's not to say that an experienced rider or driver of a motor vehicle can't perceive actual changes to the vehicle through 'seat of the pants' experience. The more experience one has, the finer this 'seat of the pants' perception is.

Take Formula One drivers for example... through thousands of miles of testing they can sense the subtle difference on track between a couple PSI of tire pressure. But when it comes to fuel, I doubt that an F1 driver would be able to tell whether the gasoline in his car had a couple more points of octane than what the engine compression ratio requires as a baseline octane number. Conversely, the driver would no doubt immediately notice poorer engine performance if the fuel octane number were below the baseline requirement for that engine. The point being that I don't think an F1 driver could be fooled into believing in a 'placebo effect' where tangible, real changes are or are not made to his car.
 

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If you indeed really did see that increase in performance, and ethanol content is the same (it is around here between 87 and 93), and brand is the same, then you are getting pre-detonation and your bike is pulling timing on 87 to compensate. That's the only way the 93 would help your bike.
That's what I was thinking as well.

I don't think the CBR has a knock sensor, so it won't adjust the timing if detonating, but the detonation will kill the power.

Detonating on the recommended octane fuel could be caused by excess build-up of carbon in the combustion chamber, which has been suggested as a possible cause for some engine damage.

Octane does not produce power - period. It only slows combustion to keep detonation from starting. Detonation kills power.

I would suggest running a strong fuel system cleaner. Techron Concentrate at 1oz per gal is excellent.

Check to see if the Premium and the Regular both contain ethanol. Generally, you will get more power from gas without ethanol, no matter what the octane rating.
 

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my biggest factor is cost... I sold my car and bought a $1500 bike so I could save money, lol

if I'm going to get higher octane, I want to get 100% gas and that's $4,00 a gallon... so double my normal 87 fill up and that will add up after time.

I also look at the availability of pure gas, there aren't very many stations that sell it in Colorado or near me, so if I have to fill up, I don't want to go out of my way to do so.


now if you live around Atlanta lets say, it's a different story, if you need to fill up, then you can find something pretty close:


Here's a map of pure 100% gas (which if you're going to run higher than recommended octane, try and run 0 ethanol.
...you can barely see anything east of the Mississippi... sorry Southwest :/



...just my thoughts...
 

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my biggest factor is cost... I sold my car and bought a $1500 bike so I could save money, lol

if I'm going to get higher octane, I want to get 100% gas and that's $4.00 a gallon... so double my normal 87 fill up and that will add up after time.

I also look at the availability of pure gas, there aren't very many stations that sell it in Colorado or near me, so if I have to fill up, I don't want to go out of my way to do so...
Looks like you've got at least a few stations in or close to Fort Collins... the Pure Gas website lists 4 stations in Fort Collins: http://pure-gas.org/index.jsp?stateprov=CO

Here in Santa Fe, NM we've got just one station selling non-ethanol 90 PON. Fortunately though it's only about $0.60 more than what the 88-89 PON mid-grade gas with 10% ethanol sells for, so right now here in Santa Fe the 90 PON non-ethanol is selling at just under $3.00 per gallon.

Back to the premise put forth in the opening post of this thread... it's not the few more points of octane making a low compression engine perform better, rather it's using a fuel which has no ethanol added to it.
 
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