Which Octane?

[drtbkeryder4]

well cheers guys, it seems its split like 60/40 to 91. I think that should do for what ill be doin eg. puttering around town. Cheers

[sugilite:Me]

Congrats. How's the race prep on your new toy coming along?

Cheers Bonez.
The 10 is coming along nicely.
An akrapovic exhaust system has arrived and that with some good tyres should see me having some fun!

[Karma]

You'd have to have a pretty radically worked high performance bike to need more than 91. The only bike I've owned that specified 95 Octane was my TRX, but then it depends on what Octane rating you are talking about RON or DIN?

Yeh, but need isn't always it though is it. Technically all your body needs is bread and water, but fucked if I'd live like that.

All I know is that on my 400 it runs much sweeter on 96/98 than it does on 91, but each to their own.

[James Deuce]

Yeh, but need isn't always it though is it. Technically all your body needs is bread and water, but fucked if I'd live like that.

No it doesn't and yes you would be fucked. Worse than if you lived on the "Supersize Me" diet.

All I know is that on my 400 it runs much sweeter on 96/98 than it does on 91, but each to their own.

I have a theory about that. It goes like this: 95/98 octane fuel costs more so my Internal combustion engine MUST run better on it.

[Fryin Finn]

You'd have to have a pretty radically worked high performance bike to need more than 91. The only bike I've owned that specified 95 Octane was my TRX, but then it depends on what Octane rating you are talking about RON or DIN?

Hot Damm Jim - I only ever ran 91 in my TRX didn't seem to harm it at all - d'you think i was missing a few GG's. Got over 60mpg from it too.

[James Deuce]

Hot Damm Jim - I only ever ran 91 in my TRX didn't seem to harm it at all - d'you think i was missing a few GG's. Got over 60mpg from it too.

To bo honest I put 91 in mine most of the time too. It specified 91 - didn't say I used it . Mind you the sticker was in Japanese, so I'm assuming the 96 in amongst the pictograms was referring to fuel.

[toymachine]

My Bandit always ran on 91 and I continued to do so until last fillup where I went 95...

Can't say I really noticed much other then it's perhaps a tad smoother and doesn't seem to get a strange rattle after long periods with VVT on...

[Karma]

No it doesn't and yes you would be fucked. Worse than if you lived on the "Supersize Me" diet.

That guys a pussy mate, I've been living on that diet for like 5 years.

I have a theory about that. It goes like this: 95/98 octane fuel costs more so my Internal combustion engine MUST run better on it.

I'm well aware of the placebo effect, and I'm not disputing that it may be partially responsible for the results I've seen, but I'm also aware that the bike runs smoother since I started using it, and that's good enough for me.

If you're a little short on cash, or just simply prefer 91, I'm sure there's no ill effects on your bike from doing so. I'm not gonna say that bikes can't use 91, just saying that both myself and my bike prefer 96/98.

[Maverick]

I normally use 98 in my bandit 250,
I find that If I use 95 I sometimes get a weak spot in my power about 8,000 rpm, doesnt happen on 98. Based on that I havent tried 91. Only use 95 when I have to, Shell 95 seems particularly bad but then thats the one I mainly had to use so cant really say for others,

Mav

[The Stranger:Me]

Do you know what pinging is or what it sounds like?
If you are getting any pinging then consider a higher octane, if not use 91 (or whatever the manufacturer specifies)

In the GSXR I use the highest octane available around town because I do get a little pinging now and then with 91. On the open road I use 91. There is no appreciable power increase with the high octane, well none that I can discern.

In the Blackbird it was cheaper to run on higher octane fuel and had a noticeable power increase. The Blackbirds have a knock sensor and retard the timing if knock is detected. Not sure, but I believe this may have impacted on the results with the blackbird.

[James Deuce]

Shell 95 seems particularly bad but then thats the one I mainly had to use so cant really say for others,

Mav

It is. Mileage is terrible too. 10-12% less than other distributors. Blame ethanol

[MSTRS:Me]

CaN, the term you refer to is 'pinking', I believe. Normally caused by too-advanced timing on low(er) octane fuel, when the engine is under load. The answer is either - increase the fuel octane, retard the timing, or best of all, never let the engine labour.
As an aside, I used 91/95/98 at various times in the 1100 - it run fine on any of them, but best on 98. Have only used 95 in the 750 so can't comment there.

[The_Dover]

The octane rating of gasoline tells you how much the fuel can be compressed before it spontaneously ignites. When gas ignites by compression rather than because of the spark from the spark plug, it causes knocking in the engine. Knocking can damage an engine, so it is not something you want to have happening. Lower-octane gas (like "regular" 87-octane gasoline) can handle the least amount of compression before igniting.

The compression ratio of your engine determines the octane rating of the gas you must use in the car. One way to increase the horsepower of an engine of a given displacement is to increase its compression ratio. So a "high-performance engine" has a higher compression ratio and requires higher-octane fuel. The advantage of a high compression ratio is that it gives your engine a higher horsepower rating for a given engine weight -- that is what makes the engine "high performance." The disadvantage is that the gasoline for your engine costs more.

I think that's a fairly good explanation of it. Why the fuck would your engine run better on a fuel that is designed to ignite at a higher compression ratio?

It's all in the mind. If your engine is not a high comp performance motor then why waste your money on higher octane fuel than you need??

It runs better, bollocks, that's like saying you get pissed quicker on poofy boutiqe beers with a lower alcohol content cos they taste nice and cost more..."it's the designer bubbles..."

load of old toss.

[onearmedbandit]

Well said Dover.

[Steam]

The official workshop manual for my mighty GN250 says "Gasoline used should be graded 85-95 octane or higher."
So now I'm confused. It doesn't make any difference to me on my whimpy GN I suppose, but it is interesting.