Topic: Preferred Gasoline

[Lavis500]

So I was reading through the CB500's owner's manual when I ran across something I hadn't seen or expected:  "It is recommended that 90 or higher octane number gasoline containing a small percentage of lead."

I don't mean to sound so young, but are our bikes meant to run on leaded gasoline?  I thought gas was either leaded or unleaded.

Also, on a second note, has anybody ever used the "park" function of the ignition switch?  How long can you leave it like that before you begin to see your battery suffering?

[weekend_junkie]

Park is a handy thing if you are stopped on the side of a highway at night for an emergency and do not want to kill your battery by having the headlight on.

You got me on the lead part.  Can't be as bad as ethanol.

[cookindaddy]

Good question about gasoline.

When I got my new (old) bike two years ago, an old timer suggested that I only wanted to use high octane gas. Leaded gas is long gone around here.

After I got all the other problems fixed with my bike (750 K8) and got it properly tuned, it seems to be very happy running standard octane gas (the regular stuff at the pump). I have tons of power with flawless performance and I am getting 54 mpg (mostly highway driving).

We have about 10% ethanol at the pumps here in Ontario Canada. Ethanol has less energy than gasoline but at that ratio it is not noticeable.

Lead of course is a very lethal material.

[TwoTired]

In the early 70's, the gas rating method in the US was standardized using the RON method and it all had lead added to it as a cheap way to prevent engine knock/ping.

Research Octane Number = RON
There are other methods of rating gasoline.   One of them is MON.
Motor Octane Number = MON

When unleaded gas became available, and to add confusion for consumers, the rating method was changed to the
(MON + RON)/2.  This became the "pump octane number" that they labeled the pumps with.  This is 4 or 5 numbers lower than a true RON rating.
http://en.wikipedia.org/wiki/Octane_rating

The lead in the gas also lubricate cast iron valve seats commonly used in engines of the era.  Without lead and under engine high loads the cast iron seat wore rapidly.  Newer engines for unleaded fuel have steel valve seats in the head.
The aluminum head on the SOHC4 already has steel seats for the valves.  So, it does not really need leaded fuel for either lubrication or an octane boost.

Cheers,

[Lavis500]

Thanks for the info, TT!  I'm glad I could get an expert to chime in on it.  I didn't think it'd be an issue running today's unleaded gas in it as I'd seen others doing this, but I really appreciate the explanation behind my findings.

[333]

The aluminum head on the SOHC4 already has steel seats for the valves.  So, it does not really need leaded fuel for either lubrication or an octane boost.

Cheers,

So true.  It was like Honda had a crystal ball.  They knew lead was going away and made their engines accordingly.


Ethanol is another story.  In the burning process, ethanol creates carbon, much more than gas without ethanol.  And carbon is harder than steel.  Not so much of a problem with cars, because higher heat is needed, as in the difference between water cooled and air cooled engines.  And the heat is even higher in 2 stroke engines.  I know of 2 products to help.  BG 44K (expensive) and Seafoam.  Use one of these in anything air cooled that you own.  The 44K might be good as a start, to clean out built up carbon.  Then Seafoam as a regular additive to keep it clean.

[1974CB750rider]

I still find my bike seems to get better mileage when I use 93 instead of 87. It doesn't cost much to fill these bikes up anyway so I always run the good stuff in mine.

[Retro Rocket]

Ethanol is crap and absorbs moisture, no wonder our American members have so much trouble with carbs and rusted fuel tanks. I refuse to use ethanol in anything, it is corrosive crap and does nothing to make the fuel any safer.....once again we have been fed mis truths and swallowed it hook line and sinker. Unleaded fuels are now much more poisonous than the leaded fuels they replaced.

Mick

[Don R]

I regularly buy race gas at the drag strip and if it was permissible to add a drip of two to my bikes gas tank for a little valve lube I would once in a while. But I don't- unless I'm going off road, yeah that's it, off road, only, thats when I do it. yeah. like if I was off road in the desert, you know, right?

[Johnie]

I only use non-ethanol in my 750's now. I just had a bad feeling every time I filled with ethanol. So I first tried it out for a while on the daily rider K4 and all ran very well. I then did the K1 and then KO. I did not notice any problems with the higher octane, but now have piece of mind with the non-ethanol.

[bird]

Australia killed off lead petrol, and my CB750 hasn't been happy since. Do any of our American and International cousins use products like Valvemaster additive to compensate for the lack of leads benefits? It's recommended here for old cars and bikes.

http://www.valvemaster.com.au/Win_ie/going.html

[Lavis500]

I wish I could escape ethanol, but in TX it seems kinda hard.  I was living it up on my summer road trip when I was going through Iowa, Indiana, Nebraska, etc.  My truck (07 chevy silverado 5.3 V8) saw an increase of 3-5 mpg. I know that doesnt sound like much, but going from 14 to 17  city and 18 to 21 highway is a drastic change!

It certainly does sound like Honda was thinking ahead of the curve.  All hail the Honda Gods.   

[Brown Bomber]

     I've been hearing lately of people getting stale 92/93 octane, because with this poor economy people are buying the lower octane to save money, and the premium sits in the tanks too long.
     I'll be switching to 89 octane, and adding some sort of octane boost, as soon as I figure out which octane booster to try. So far all the products I've seen claim to do miracles, but don't tell you what's in them. Is that a real poncho, or is that a Sears poncho?
     Any suggestions?

[ferroussphinx]

hello brown bomber 






check out myth busters   they did a test on all the major brand octane boosters and found that they did not help at all  in fact they reduced mileage and power in all live tests     

[dave500]

i use 98 in everything bird,i only used an additive once ,at half the dose and got red/orange deposits on my pistons and plugs,i threw the rest out.

[Gordon]

     I've been hearing lately of people getting stale 92/93 octane, because with this poor economy people are buying the lower octane to save money, and the premium sits in the tanks too long.
     I'll be switching to 89 octane, and adding some sort of octane boost, as soon as I figure out which octane booster to try. So far all the products I've seen claim to do miracles, but don't tell you what's in them. Is that a real poncho, or is that a Sears poncho?
     Any suggestions?

Why do you need the higher octane rating?  Is your engine modified for higher compression? 

[flybox1]

87, and a splash of seafoam.
 

[Brown Bomber]

     I've been hearing lately of people getting stale 92/93 octane, because with this poor economy people are buying the lower octane to save money, and the premium sits in the tanks too long.
     I'll be switching to 89 octane, and adding some sort of octane boost, as soon as I figure out which octane booster to try. So far all the products I've seen claim to do miracles, but don't tell you what's in them. Is that a real poncho, or is that a Sears poncho?
     Any suggestions?

Why do you need the higher octane rating?  Is your engine modified for higher compression? 

Just trying to go by the book;

[Deltarider]

Why do you need the higher octane rating?  Is your engine modified for higher compression?

Carbon can do that. In the Netherlands back then it was advised to tank leaded fuel every fourth time (for lubing effect).
 

[Deltarider]

Unleaded fuels are now much more poisonous than the leaded fuels they replaced.

Nonsense, it's not as you put it. Do some study. You can start with a search in Wikipedia.

[TwoTired]

     I've been hearing lately of people getting stale 92/93 octane, because with this poor economy people are buying the lower octane to save money, and the premium sits in the tanks too long.
     I'll be switching to 89 octane, and adding some sort of octane boost, as soon as I figure out which octane booster to try. So far all the products I've seen claim to do miracles, but don't tell you what's in them. Is that a real poncho, or is that a Sears poncho?
     Any suggestions?

Why do you need the higher octane rating?  Is your engine modified for higher compression? 

Just trying to go by the book;

Which book is that?
AFAIK the 77-78 CB750F had the highest Comp. ratio of all the Cb750s.  See Below

[cobra2411]

Ethanol is crap and absorbs moisture, no wonder our American members have so much trouble with carbs and rusted fuel tanks. I refuse to use ethanol in anything, it is corrosive crap and does nothing to make the fuel any safer.....once again we have been fed mis truths and swallowed it hook line and sinker. Unleaded fuels are now much more poisonous than the leaded fuels they replaced.

Mick

Yeah but if we didn't use Ethanol our corn farmers would starve, the planet would reach 1 billion degrees - killing all the polar bears and the terrorists would win... 

I run 93 Sunoco because my Mustang GT likes it so much and it's not that much more expensive... Overkill maybe but that's my middle name.

[Duke McDukiedook]

Higher octane will burn slower so you would have to retard your advance to get the maximum efficiency out of a higher grade octane.

Unless you have problems with pinging or knocking you are literally pissing your money away and getting no benefits out of it whatsoever unless the higher grades don't contain ethanol. I don't care to monkey around with my ignition timing any more than I have to because the regular 87 works fine.

If ethanol becomes a problem with my bike and they definitely do not mix ethanol in the higher grade I might consider it down the line.

[TwoTired]

Higher octane will burn slower so you would have to retard your advance to get the maximum efficiency out of a higher grade octane.

I think you'll find this is exactly backwards.  With a slower igniting fuel you can ADVANCE the timing.

Pinging engines can sometimes be fixed by ignition retard.  But, you often lose some power band doing this.  It is an RPM related trade off.

Cheers,

[Deltarider]

Higher octane will burn slower

Another discussion turning academic, I'm afraid, but I'll be a sport...
Can you tell us HOW MUCH slower?