Topic: 75 honda cb550k1 four correct octane to run?

[JACKOCASTER75CB550K]

Ok guys here is a contraversial question:What octane should I run for best performance 87-89-93 The manual says 91 or higher..Please inform...

[LesterPiglet]

We get 95 in Uk as the lowest, my bike runs fine.

[DJ_AX]

From what I've gathered ... todays 87 is equivalent to the 1970's specs required...
I've run fine with it for the last 30,000+ miles.

Ethanol is the thing to avoid if you can.
Unfortunately for me I can't get ethanol free gas around me so ..
I've run fine with it for the last 30,000+ miles.

[Dave Voss]

My CB550 owners manual states "91 Research Octane -or- 86 Pump Octane", and I believe 'pump' octane is actually the average of research octane and motor octane, typically expressed as '(R+M)/2' which is what USA stations state on their pumps.  So, the 87 octane that most USA stations offer as the lowest grade gas would be acceptable, as it is one point higher than the minimum recommended by Honda.  Most air cooled engines do not have very high compression ratios, and so lower octane pump gas is normally used by many owners.

[stereosilence]

You want Regular Unleaded (87). It will run worse if you use something else (unless you have a timing problem possibly).

Ditto on the ethanol. Using some seafoam is probably a good thing.

[sniper1]

What will seafoam do for you? Do you just dump it into the tank?

[Dimitri13]

My suggestion is to find an ethanol-free gas station and use that. http://pure-gas.org/index.jsp?stateprov=VA

Otherwise just use regular (87) and don't let it sit for too long.

[InTheStreet]

I have never had any hint of pre-ignition, even when I had the ignition timing well advanced due to guessing, and I run 87. And I just put in new rings and honed the cylinders and broke it in.

I don't know why I would pay more for gas if I don't need it.  Why do people act like higher octane is better?  I feel like by that logic, I should use the biggest socket I can find on everything because it has a bigger number on it.

That's my rant/two cents.

[Stev-o]

I've used all octanes - 87, 89 & 93 and can not tell the difference.

The real question is:

What is the best oil?!

[72 yellow]

From what I've gathered ... todays 87 is equivalent to the 1970's specs required...
I've run fine with it for the last 30,000+ miles.

Ethanol is the thing to avoid if you can.
Unfortunately for me I can't get ethanol free gas around me so ..
I've run fine with it for the last 30,000+ miles.

There is a station where Southfield Fwy ends in Allen Park.  On the corner of Pinecrest and Southfield.  Sells ethanol free 90 octane. 

[stereosilence]

High compression engines run on higher octane. My Nissan Maxima runs on it.

Sea foam has cleaning agents and acts as a fuel stabilizer. As I understand it, ethanol absorbs air moisture into the gas. Sea foam (or other fuel stabilizers) help neutralize the effects of this. I run it in my lawn equipment gas (since it sits a good bit) and also put it in my tanks in the winter time when I don't ride as much. Never had any problems with varnish or anything like that.

Ethanol is terrible for your components. Here in Atlanta Ga. it is required at all gas stations. It ruins your O2 sensors and catalytic converters which we then have to pay to replace to pass emissions to register our cars. So, we subsidize corn with taxes to make ethanol, which we are forced to buy, which degrades our performance and gas mileage and ruins our vehicles, which we are forced to fix before we are forced to pay to have our "emissions" checked before we are forced to pay taxes to register the car. All because the government feels that cow farts are destroying the atmosphere.  That's my rant.

[Dimitri13]

Dont use synthentic if you have even the slightest oil leak for it will make it worse and proly find new leaks..

Oh god this.

[JACKOCASTER75CB550K]

Oh god What?

[Stev-o]

This

[Black 750K8]

You mean that