Topic: Which fuel should I use...

[Chris_MI]

I am a fairly new owner of a '82 Honda 650 Nighthawk.  I'm not real clear on which grade of fuel I should use in my bike.  The owner's manual says use automotive grade fuel of at least 86 octane, or "research grade of at least 91 octane...".  Everyone I've talked to burns premium 93 octane.  That's what I use, and once I used 87 octane and I didn't notice any ill effects.  Can you guys shed some light on this for me?  Thanks.

[OldSchool_IsCool]

Welcome to the forum Chris!  I'm sure you will get lots and lots of advice on this topic, here are my $0.02

High octane fuel is made mostly for high-compression engines.  10:1 or above as a rule of thumb.  High octane will not give you more power, it will not improve your milage.  If your engine runs well on 87, use 87!

By the way, I'm over in Battle Creek.  Hope to see you on the road some day!

[croquesaveur]

Use the lowest grade you can run without the engine knocking.  If your bike is tuned properly this is the cheapest grade available.

Higher octane just refers the the fuel's resistance to pre-ignition (detonating before the spark).

Using an unnecessarily high octane won't hurt you, but you will NOT get better mileage or performance.

[ProTeal55]

87 all the way.
Unless a motor has decent compression their is no reason to run anything higher.
You can actually over-octane a motor, and the thing will run slower/loose HP...

[johnny-from-bel]

87 all the way.
Unless a motor has decent compression their is no reason to run anything higher.
You can actually over-octane a motor, and the thing will run slower/loose HP...

If you look at the carnot cyle and its energy yield octane does not come into the equasion.
You could probably octane fuel so high it won't burn but that would be way over what you can buy.

I normaly run my 750 on 91 RON but I have run it on 100 RON. Did not notice any difference.
100 RON octane is the highest I can buy.

*EDITED* removed the US octane ratings they where wrong anyway

[Trevor from Warragul]

I know a guy through another bike club who used to work for one of the major gas companies - he said use the more expensive high octane stuff, not because of the octane rating, but because it's just better quality (I think his actual quote was "It's not like the crap you get in regular gas, the company has actually spent money refining it").

[Gordon]

I know a guy through another bike club who used to work for one of the major gas companies - he said use the more expensive high octane stuff, not because of the octane rating, but because it's just better quality (I think his actual quote was "It's not like the crap you get in regular gas, the company has actually spent money refining it").

The standards may be different in other countries, but in the U.S. all grades of gasoline come from the exact same base stock and are federally required to meet the same minimum levels of anti-deposit additives.  The only physical difference between the grades is what is added to increase the octane rating. 

[333]

Back in the day, I was always told to run low octane, and tune it to that octane.That was before computers controlled our cars.  I don't know if it was true, but I've tried to do this and it seems to do OK.  I've found that sticking to national brands, I have the least problems.  I haven't had to use any dry gas in years.

[OldSchool_IsCool]

I've had no issues with running 87 with a ounce of SeaFoam per gallon in every tank. 

Awww screw it!  I'm just going to convert my bike to Hydrogen! 

[edbikerii]

I've noticed that Getty is consistently less expensive than other brands in this area.  However, the only time i've ever gotten a crappy tank of gas was from a Getty station.  I've always been under the impression that all the gas came from all the same refineries, and the brand really made no difference, but now I shy away from Getty due to that bad experience.  I supposed it could have been that one gas station having problems or somehing.

I've been using 87, but just tried a tank of 92.  So far, I'm not noticing any difference.  I suspect I won't, so I'll stop throwing money away and switch back to 87.

[johnny-from-bel]

I know a guy through another bike club who used to work for one of the major gas companies - he said use the more expensive high octane stuff, not because of the octane rating, but because it's just better quality (I think his actual quote was "It's not like the crap you get in regular gas, the company has actually spent money refining it").

The standards may be different in other countries, but in the U.S. all grades of gasoline come from the exact same base stock and are federally required to meet the same minimum levels of anti-deposit additives.  The only physical difference between the grades is what is added to increase the octane rating. 

Same in Europe. Used to work at the Exxon refinary in Antwerp. Same basic stuff for all grades. Only thing that was different where the aditives that where added after the refinary process.

[croquesaveur]

Refineries in the US share the same pipe system for distributing gasoline.  The gas added to the system is tested to make sure that it meets federal and state requirements.  There's no way to separate the batches to the system, so the pipe system works more like a bank account: adding 1000 gallons in one place lets a 1000 gallons be taken out somewhere else --the gasoline taken out is not necessarily the same gasoline put in.

This is something that the oil companies don't tell you about (for obvious reasons).  The gasoline you buy anywhere is essentially the same regardless of the brand.

The only thing that is different from one brand to the next are the additives in the gas which are added after the gas is removed from the pipeline.

http://www.eia.doe.gov/neic/brochure/gas06/gasoline.htm

[RiceBurner]

Owner Man. says something like 92 or 93.........i run shell 91 the bike seems to run smother and a lil happier ........the higher the octane the cooler it gonna burn............w/ low octane you can get pre detonation which is baaaad................But whatever you decide to run i'd put a little bit of an oil based fuel additive like marvel mystery or lucus

[bobsmith]

I agree totally with rice burner about adding the Marvel Mystery oil to a air cooled engine. (not to change the subject) On a 2000 mile trip I used different octane grades, and allowing for speed, hills, wind, and all that other fancy stuff we cant really equate, I seemed to get maybe 1 more mpg with 93. Maybe my timing was a little advanced to take advantage, another unknown.  I stick with 87 for the price difference.

[croquesaveur]

The octane in the owner's manual is RON (Research Octane Number).  The other way of measuring octane is MON (Motor Octane Number).  Gas pumps in North America post the rating as the average of the two ratings: (R + M) / 2.

When the owner's manual tells you to use 91 RON octane you should use 87 posted octane.

See question #2 here: http://retail.petro-canada.ca/en/independent/2069.aspx

Using an unnecessarily high octane will not give you any advantage.