Octane ratings

[Guest EternalDragon]

Been having an argument with a 250 Ninja (with a carb) owner. Both the NC700x manual

and the 250 manual says to use 91 octane gas.

 

My Honda tech said 89 is fine and is what I have been using for 800+ miles with no

problems.

 

The 250 ninja is definitely lower compression. He says he gets engine knock using

89 octane. I say there is no difference in 2 octane numbers higher. I have never heard

of a bike knocking before. My old 400cc Honda manual said use 87 or higher. That was

dual carbs.

 

I do know 89 burns smoother or something so what is best?

[Guest EternalDragon]

Just found out that the Ninja and my NC700x is the RON rating. Which is 8-10 points higher

than the USA and Canada system which uses MON.

 

So 91 RON in the manual is actually around 81-83 octane here in the U.S.A.

[Guest motorboy]

Nope reg 87 is what the USA NC's should use   to long of and answer about ron&mon look it up good reading

[wozza 967]

We only have 2 grades these days in the UK. Regular unleaded and super unleaded both of which have higher octane ratings. It's funny really because I use to try and do up 70s and 80s Jap bikes imported from both the US and Japan and the Carbs were always blocked up with gum whereas UK machines were never as badly effected by gummed up carbs. Basically as far as I can see the US and Japan use crap quality fuel though I don't know the reasons for this.

Edited March 9, 2013 by wozza

[Guest engasal]

I stick whatever 97 I can get, I find Texaco flavour is the best for power

[Guest Crusty]

In the UK, regular is 95 RON and super ranges from 97 to 100 depending where you buy it.

[michael 324]

Owner's manual.

Whatever the owner's manual recommends. After all, if we acknowledge they've engineered a fairly decent motorcycle here, the least we can do is agree with their fuel recommendation.

And if your motorcycle "pings," on acceleration or under load, splash in a higher octane fuel. Here in NA, we've got the issue of ethanol (which in my most humble opinion is a degrading use of corn that can be imagined. It should be in polenta, corn bread, corn tortilla's, corn on the cob in a crab boil....anything but in my fuel) which aides in the degradation of the fuel, so I"m particularly sensitive to fuelling issues.

[Guest motorboy]

I stick whatever 97 I can get, I find Texaco flavour is the best for power

Where do you find 97 in the USA in pump gas did your finger slip and you meant 87 and for some reason mine likes Shell 87 the best I can feel the different.. 

[Guest motorboy]

Over here the short answer is R+M/2 which is you add ROM & MON and divide by 2 and get North American rating so your 95 is our 87 and so on.....

[Guest motorboy]

We only have 2 grades these days in the UK. Regular unleaded and super unleaded both of which have higher octane ratings. It's funny really because I use to try and do up 70s and 80s Jap bikes imported from both the US and Japan and the Carbs were always blocked up with gum whereas UK machines were never as badly effected by gummed up carbs. Basically as far as I can see the US and Japan use crap quality fuel though I don't know the reasons for this.

Years ago we did have good long lasting gas but for the last 10 years or so the gas self life has gotten shorter and shorter right now REG will turn to gum in as little as 30 days super 90 days that our GOVT at work trying to protect use from somthing

[Guest engasal]

I stick whatever 97 I can get, I find Texaco flavour is the best for power

Where do you find 97 in the USA in pump gas did your finger slip and you meant 87 and for some reason mine likes Shell 87 the best I can feel the different.. 

 

Texacos around here do 97 octane, not a typo

[Guest EternalDragon]

Interesting topic if researched. It seems people have heated debates on the topic

of what grade gas to use in various motorcycles.

 

Basically it depends on compression ratio. The NC700 has a 11.6 to 1 ratio. Kind

of high but not as high as a 600 or 700 street bike. 89 (USA RON+MON/2 rating)

would run fine. I think that would be like 95 RON in other countries but not sure.

Canada and USA use a different measure or octane.

 

Anything like 12.5 to 1 or higher compression would best run on the premium gas. It has a

longer stroke to achieve burn so it would run better on the slower burning, higher premium gas.

[wozza 967]

Interesting topic if researched. It seems people have heated debates on the topic

of what grade gas to use in various motorcycles.

Basically it depends on compression ratio. The NC700 has a 11.6 to 1 ratio. Kind

of high but not as high as a 600 or 700 street bike. 89 (USA RON+MON/2 rating)

would run fine. I think that would be like 95 RON in other countries but not sure.

Canada and USA use a different measure or octane.

Anything like 12.5 to 1 or higher compression would best run on the premium gas. It has a

longer stroke to achieve burn so it would run better on the slower burning, higher premium gas.

There are no debates in the UK, we just fill our bikes up and away we go. If someone decides on Super unleaded route that's fine, but I don't think the slight benefit warrants the extra cost. Edited March 10, 2013 by wozza

[Guest motorboy]

Interesting topic if researched. It seems people have heated debates on the topic

of what grade gas to use in various motorcycles.

 

Basically it depends on compression ratio. The NC700 has a 11.6 to 1 ratio. Kind

of high but not as high as a 600 or 700 street bike. 89 (USA RON+MON/2 rating)

would run fine. I think that would be like 95 RON in other countries but not sure.

Canada and USA use a different measure or octane.

 

Anything like 12.5 to 1 or higher compression would best run on the premium gas. It has a

longer stroke to achieve burn so it would run better on the slower burning, higher premium gas.

You lost me at long stroke to achieve better burn   I don't want it to sound like I'm coming down on you but I think if you read up on engine design you would learn a lot    nothing wrong with not knowing just knowing how thing works will make it all better  like I said please don't take it the wrong way I just like to get things right   any way who am I in a past life I was a Master Honda Mech (22 schools) for many years and I worked with American Honda on many projects 1969 CB750 -1971 QA50- 1970 ATC 90 (the first ATC) and many more   American Honda use to call me their go to guy   I worked for the largest selling dealer in the nation and if  anything was giving a problem I saw it first and was trying to figure it out by time  they called  so over the years I learned a thing or two and built many an engine both street and race now I'm retired and  work with a few dealers only on old stuff   i like before 1980  .I hate to work on my own bikes but do   I have read many thing on sites that's not right but have to hold back as I don't want to sound like a know it all   so please that all this with a grain of salt   I'm done

[Guest Crusty]

I'm with wozza on this. As we only have two grades available in the UK it's never really been a debate here. Almost everyone uses regular (interestingly officially called 'premium') petrol in all types of vehicles with no issues.

Some people do spend the extra on super unleaded, but they are a tiny minority.

[Guest Stu]

I'm with wozza on this. As we only have two grades available in the UK it's never really been a debate here. Almost everyone uses regular (interestingly officially called 'premium') petrol in all types of vehicles with no issues.

Some people do spend the extra on super unleaded, but they are a tiny minority.

I've tried to find some sales data but unsuccessfully. I don't agree that the fuel companies and forecourts go to all that effort of providing Super unleaded for a tiny minority of people to buy it. I'm sure a lot of people buy Super. Look at engasal who wastes money on Super unleaded on a bike that can get absolutely no benefit from it and the whole point of the NC is to save you money on petrol

[Guest Crusty]

Well, fair enough. My point wasn't particularly about the numbers of people buying / not buying super unleaded, or indeed the pros and cons, but more about the fact that there are two grades available.

[Guest EternalDragon]

Interesting topic if researched. It seems people have heated debates on the topic

of what grade gas to use in various motorcycles.

 

Basically it depends on compression ratio. The NC700 has a 11.6 to 1 ratio. Kind

of high but not as high as a 600 or 700 street bike. 89 (USA RON+MON/2 rating)

would run fine. I think that would be like 95 RON in other countries but not sure.

Canada and USA use a different measure or octane.

 

Anything like 12.5 to 1 or higher compression would best run on the premium gas. It has a

longer stroke to achieve burn so it would run better on the slower burning, higher premium gas.

You lost me at long stroke to achieve better burn   I don't want it to sound like I'm coming down on you but I think if you read up on engine design you would learn a lot    nothing wrong with not knowing just knowing how thing works will make it all better  like I said please don't take it the wrong way I just like to get things right   any way who am I in a past life I was a Master Honda Mech (22 schools) for many years and I worked with American Honda on many projects 1969 CB750 -1971 QA50- 1970 ATC 90 (the first ATC) and many more   American Honda use to call me their go to guy   I worked for the largest selling dealer in the nation and if  anything was giving a problem I saw it first and was trying to figure it out by time  they called  so over the years I learned a thing or two and built many an engine both street and race now I'm retired and  work with a few dealers only on old stuff   i like before 1980  .I hate to work on my own bikes but do   I have read many thing on sites that's not right but have to hold back as I don't want to sound like a know it all   so please that all this with a grain of salt   I'm done

By long stroke I meant larger compression area. Doesn't the piston have farther to go to spark the fuel?

Hence the need for higher octane in bigger cc race bikes.

 

Perhaps it would have been better to just set me straight on the facts. I don't mind learning more or finding

my thinking or info is wrong. It's all good here.

[Guest motorboy]

 

Interesting topic if researched. It seems people have heated debates on the topic

of what grade gas to use in various motorcycles.

 

Basically it depends on compression ratio. The NC700 has a 11.6 to 1 ratio. Kind

of high but not as high as a 600 or 700 street bike. 89 (USA RON+MON/2 rating)

would run fine. I think that would be like 95 RON in other countries but not sure.

Canada and USA use a different measure or octane.

 

Anything like 12.5 to 1 or higher compression would best run on the premium gas. It has a

longer stroke to achieve burn so it would run better on the slower burning, higher premium gas.

You lost me at long stroke to achieve better burn   I don't want it to sound like I'm coming down on you but I think if you read up on engine design you would learn a lot    nothing wrong with not knowing just knowing how thing works will make it all better  like I said please don't take it the wrong way I just like to get things right   any way who am I in a past life I was a Master Honda Mech (22 schools) for many years and I worked with American Honda on many projects 1969 CB750 -1971 QA50- 1970 ATC 90 (the first ATC) and many more   American Honda use to call me their go to guy   I worked for the largest selling dealer in the nation and if  anything was giving a problem I saw it first and was trying to figure it out by time  they called  so over the years I learned a thing or two and built many an engine both street and race now I'm retired and  work with a few dealers only on old stuff   i like before 1980  .I hate to work on my own bikes but do   I have read many thing on sites that's not right but have to hold back as I don't want to sound like a know it all   so please that all this with a grain of salt   I'm done

By long stroke I meant larger compression area. Doesn't the piston have farther to go to spark the fuel?

Hence the need for higher octane in bigger cc race bikes.

 

Perhaps it would have been better to just set me straight on the facts. I don't mind learning more or finding

my thinking or info is wrong. It's all good here.

No sorry again makes no sense stroke has nothing to do with compression area that would be the bore   it would be better if you looked it up on the net like under theory  of 4 stroke operation and read than for me to tell you I think you would learn more may be 2-3 hours you would have a good under standing of how things work on a 4 stroke   now the simple 2 stroke three moving parts that one seems to blow at lot of minds   I'll leave you with a brain teaser on a 2 stroke which is a richer 40 to 1 oil- gas or 50 to 1 oil= gas and why.. Just the idea of asking question shows me that you want to learn and that is good ...I have trained many a mech over the years the ones that did the best asked the most  questions

[Guest EternalDragon]

Motorboy, I looked it up and right away I see intake stroke, combustion stroke, compression stroke and

exhaust stroke.

 

Nothing different there than what my basic knowledge holds. A larger cc engine with higher a compression

rating like 12.7 to 1 should be able to utilize higher octane gas but a smaller 10.5 to 1, 250cc engine would not benefit.

It would basically fire the same as the lower octane because of lower compression rate. I am talking normal at the pump

low, mid and premium gas.

 

"Higher compression ratios produce more power, up to a point. The more you compress the air/fuel mixture, however,

the more likely it is to spontaneously burst into flame (before the spark plug ignites it). Higher-octane gasolines prevent

this sort of early combustion. That is why high-performance cars generally need high-octane gasoline -- their engines

are using higher compression ratios to get more power."

[Guest motorboy]

Motorboy, I looked it up and right away I see intake stroke, combustion stroke, compression stroke and

exhaust stroke.

 

Nothing different there than what my basic knowledge holds. A larger cc engine with higher a compression

rating like 12.7 to 1 should be able to utilize higher octane gas but a smaller 10.5 to 1, 250cc engine would not benefit.

It would basically fire the same as the lower octane because of lower compression rate. I am talking normal at the pump

low, mid and premium gas.

 

"Higher compression ratios produce more power, up to a point. The more you compress the air/fuel mixture, however,

the more likely it is to spontaneously burst into flame (before the spark plug ignites it). Higher-octane gasolines prevent

this sort of early combustion. That is why high-performance cars generally need high-octane gasoline -- their engines

are using higher compression ratios to get more power."

You have some good points  but over all it's just not that simple as I said compression is only one factor in how much octane an engine needs    but I think enough has been said on the subject....