High Octane?

[yamahamer]

What is the highest Octane anyone has run in a Royal Star? I am going to have another dyno done and was looking at raceing fuel. My choices are 100, or 111 octane. Will the pistons handle the 111 or will they melt?

[george c]

i would not go with race fuel.

I us-to put it in my race bike and after a full day of running sprints.

you would have to change the spark plugs.

the extra octane on a street bike is not worth the price of the fuel or the cost of spark-plugs.

Just my

George C.

[timgray]

If you are running standard carbs and did not tune for the higher octane you will get no difference.

 

High Octane has no more power than regular gas, it simply has more resistance to ping and knock. A Z06 vette makes more power with 108 racing gas because it can adjust timing more radical. your bike cant. also your bike does not have the 11:1-12:1 compression ratio it needs to even take advantage of racing fuel, you will need to adjust timing, increase compression or add a turbo to get any benefits out of anything above the regular 87 octane gas.

 

Now the racing fuel with Nitro in it, that's a completely different story... I'd not run nitro in anything I want to keep for a long time. That's my racing and hotrod experience talking there, nitro is evil stuff.

[GG54172]

High octane fuel actually has less power per gallon than low octane. It ignites at a higher temperature and burns cooler than 87 octane fuel. The performance gain is from increased compression ratio and ignition timing available because of detonation resistance.

[CMIKE]

My experience with race fuel

We run 114 octane in our YZ250F race bikes. Usually with a straght race fuel without high compression pistons you will not see any real increase in performance with the higher octane fuels. We mixed some race fuels with perminum gas in some stock engines and had pretty good luck with them. Not that much power gain but better throttle response out of the curves or off the line. Seems premium gas is not consistant.

 

Some race gases use alcohol to increase octane...some use LEAD. Look at the MSDS sheet to determine how they are making the increased octane. I do not like an alcohol race fuel.

 

Now Oxygenated race fuel is a different story. It has been banned by the AMA for Motorcross due to the advange gain for the 4 stroke over the 2 stroke engine. This really makes a 4 stroke sing. But it is a nasty stuff. It is hard to store and will loose all its go really fast if not kept in a tightly sealed steel container Most of it is corrosive to aluminum and if it sit in the carbs it turns to a glue like substance overnight. We ran it for a short while and it would make a stock bike go...and go hard. But it took a while to get the fuel system straight afterwards.

AMA checks oxygen content at the pro races...and standard pump gas has a slight amount of oxygenate in it and lots of pump gas will not pass thier test.

 

Pistons melt?

In my experience with dirt bikes that turn 14500 RPM if you are not using nitro or some other really bad ass stuff...I have never heard or seen a melt a piston. You will probably gald a piston first. It will look like it has melted but friction caused most of the damage not the heat from the gas.

Of course you need to tune the carbs for the race gas...jetting and fuel/air mixture so and not run it to rich. A rich condition (they say) can wash the oil film off the cylinders and cause the piston to gald the cylinder. It kinda makes sense but I cannot verfy this. In a 2 stroke a lean or rich condition will take out the crank or ruin the cylinder or piston quickly. I have seen this happen on a 2 stroke many times espcially on some other brand race bikes that come from the factory set really lean.

 

I have one of those non contact infared temperature devices I use on the starting line to check temp of the engine and radiators before and after a race. You want the engine warmed up good but not too hot. It has no fan so sitting and idling with heat it up quickly in the summer. Anyway...I have found the engine actually runs cooler with a good high octane race fuel. Surprized me also. I found this on a 2 stroke and the 4 stroke bikes.

 

IF I were gonna dyno a RSV...I would get a good premium gas like maybe that AMOCO White gas...BP ultimate I think and try that...or what ever you have good luck with.

 

I got a drum of 114 leaded if you want to add some to the mix just to see...

$8.50 gallon it is a pretty blue color and smells funny.

 

I would really like to hear the results of this...very interesting.

[GeorgeS]

Just wasting money in these engines, they run just fine without it.

 

Money would be better spent on a Carb Sync tool !

[jrcain32]

Hey Mark, let know how your's runs on higher octane. I tried running 93 in mine and it ran like crap. Spit and sputtered and was hard to crank. I went back to 87 and all was well. Strange but true...

[yamahamer]

I have a carb tune. I know I'm not going to get more horsepower by fuel but I want to run something clean with no ethinol and maybe gain some throttle response. I just don't want to do any damage in the prosess. Thanks for the input I will probley just get 100 octane and check the sync one more time.

[50btripn]

I'm sure this has been asked/discussed (in another forum maybe?) so I will apologize beforehand for repetiveness...

 

I now understand the "concept of racing fuel and why it's not useful in our bikes...but what about 93 octane vs. 87? Advantages? Disadvantages? Am I wasting my $$$ wputting the 93 octane in my bikes?

[1BigDog]

My .02: I have used 107 octane years ago in my Chevelle which had 11.5:1 compression. The RSV has 10.1 compression. I personally use 89 octane in it. Most say 87 is fine for this bike but in my experiences 89 works better, at least for me. 93 didnt do a thing.

[KiteSquid]

A good reflux still would work, but would be an explosion hazard.

 

You might try a 4A molecular sieve but you would have to filter the fuel to make sure the 4A molecular sieve material was removed from the fuel.

 

And you would have to properly dispose of the material... be ready to pay $$$$$$ as the EPA would not be happy with it.

 

To save some $ on disposal fees you might be able to set up a self reactivating 4A molecular sieve.

 

 

 

 

You can test pump gas for the percentage of ethanol with a tool like this:

 

Testing fuel for ethanol

 

 

The following test can be performed to determine the presence of ethanol in gasoline.

 

On a test tube or olive bottle, make a permanent line about two inches from the bottom.

 

Fill with water to this line, then fill the tube to the top with gasoline.

 

Cover the tube, agitate it then let it stand.

 

Ethanol mixes with water and the two will separate out together. Therefore, after mixing the water and the gasoline, if the water level appears to have increased, then the fuel contains ethanol and should not be used.

 

 

there is a kit sold HERE