when it comes to gas how low is too low on octane?

[Anonymous]

So here is my next question for the masses:
I know that if you run too high octane gas you will burn too hot and you can burn you valves. You can tell that you are burning too hot by your sparks and if your exhaust pipes are turning blue. Well I havent cheacked my sparks yet ( thought it is on my list of things to do) but my down pipes have been turning blue so I was told I am burning too hot. I was running 93 octane but I kicked it down to 89 when I was told 93 realy was too high for a '79 (btw I have a '79 GS1000E). Well my pipes were still seeming to continue to turn blue-er and I have been having tremendous emounts of heat comming off the block. This is my first summer of realy riding so I dont know how much of the heat thing is normal. I have dropped the gas now down to 87 octane (regular) and some of the heat feels to have gone down along with a little bit of power but it still has no problem flying up very steap hills and I am a VERY big boy. But I dont know what can happen from me burning gas too low in octane.....any one know?

[jimcor]

87 octane is just fine for your bike. Anything higher is just a waste of money. That's all I run in both my bikes. Rule of thumb, if it doen't knock or ping, everything is fine.

That loss of power was all in your imagination.

[DMPLATT]

My Factory Manual says to run 89 octane. I used to run Super in my bikes. Now I realize it's not necessary. I run 89 and all is well. Only a few more cents than 87, so I'll go by what the manual says.

[rphillips]

I've never heard that 93 octane will run too hot, nor harm anything, just waste money. I wouldn't recommend 110 octane airplane or racing fuel, but I don't see 93 harming a thing. Usually blue pipes mean too rich or too lean.

[jimcor]

No guys. Blue chrome means it is most probably an aftermarket exhaust. Single walled and less than stellar plating. Your stock exhaust will blue too, and they are doubled walled at 'hot spots'. It does not neccessarily mean you are running too lean, and hot. Chrome blues, simple as that. The new Harley and other cruiser pipes are running a big chrome beauty pipe around the true exhaust pipe so it doesn't get hot or blue.

[rphillips]

I agree, the aftermarkets will discolor a lot quicker than the double wall stock pipes. But a good quality aftermarket pipe on a good tuned & jetted bike, may turn a slight gold color, & never turn blue. Stock pipes on a bike that is too rich or too lean will also turn blue & purple, but certainly not as quick as an aftermarket. In my opinion, jetting is the #1 cause of blueing, and vote quality of pipe & chrome the #2 cause. Just my opinion

[Anonymous]

Take it from someone who used to be a marketing rep for a major oil company ... The only thing that octane measures is your engines ability to resist knock. As stated above, if it doesn't knock you're fine. I don't believe higher octane gas would have anything to do with how hot the gas burns.

Check out the link below, this is from the Fedewral Trade Commision site:

http://www.ftc.gov/bcp/conline/pubs/autos/octane.htm

[Hoomgar]

Higher octanes will run cooler if anything at all. Run what is recommended. If your bike doesn't run good on it then go up a grade until it does. This is an indicator of engine troubles though and you should look into that. For a 78, 79, 80 or whatever old GS1000 87 octane is what you should run. And it should run fine. Higher octane will never hurt it and is a cleaner fuel too so if you want to pony the extra few cents it wont hurt a thing but it isn't needed.

There are many opinions on this subject here and all based on experience. I am afraid you?re going to have to sort this one out for yourself. The guys on this forum cannot agree on this subject or motor oil for that mater. Chain vs shaft is another issue entirely

[gspaul]

Bikes come with ...............CHAIN'S !

[jimcor]

Ah now, we all agree gas and oil are good. But... your higher octane fuels have additives that allow them to burn slower. More additives, more deposits, not a cleaner fuel. Although some higher octane fuels do have a detergent that helps to supposedly keep fuel injectors clean. :twisted:

[Hoomgar]

Ah now, we all agree gas and oil are good. But... your higher octane fuels have additives that allow them to burn slower. More additives, more deposits, not a cleaner fuel. Although some higher octane fuels do have a detergent that helps to supposedly keep fuel injectors clean. :twisted:

See what I mean? And Jim is one of the good guys!!! 8O :roll:

Wait until the forcefully opinionated ones show up!

[Anonymous]

Well nice to see we have all come to a conclusion. :roll: the person that told me that running too high octane could burn out your valve seals has been riding for over 30 years and said he burned them out in one of his older bikes because of the gas. But I am gonna just keep riding around and if something brakes...well then I guess I can fix it or get a new bike lol :twisted:
now that I am trying to hear my engine running wierd I am not sure if any of the noise is new or old. I think it is making a new sound on the lower octane but it is only at high speed ( over 60 mph) and it may have been ther before I guess I will just keep guessing lol Thanks guys

[mark]

Just to add to the confusion, my understanding is that what could burn out valves in older bikes is the unleaded fuel, it wasn't an octane issue. Older bikes needed leaded gas to cool the valves and were designed with somewhat "softer valves". Valves were redesigned with the onset of unleaded gas.

[jimcor]

Just to add to the confusion, my understanding is that what could burn out valves in older bikes is the unleaded fuel, it wasn't an octane issue. Older bikes needed leaded gas to cool the valves and were designed with somewhat "softer valves". Valves were redesigned with the onset of unleaded gas.

The lead in fuel didn't cool the valves it lubricated them. But of course they ran cooler because of less friction. So I guess, in the end we're talking about the same thing.

Speedie, I've been riding 8 years longer than your 30 year riding pard and too high an octane burning out valve seals is...Hogwash.

[mcycle-nut]

Just to add to the confusion, my understanding is that what could burn out valves in older bikes is the unleaded fuel, it wasn't an octane issue. Older bikes needed leaded gas to cool the valves and were designed with somewhat "softer valves". Valves were redesigned with the onset of unleaded gas.

The lead in fuel didn't cool the valves it lubricated them. But of course they ran cooler because of less friction. So I guess, in the end we're talking about the same thing.

Speedie, I've been riding 8 years longer than your 30 year riding pard and too high an octane burning out valve seals is...Hogwash.

I think his friend is confused. If you ran unleaded fuel in older vehicles (50's. 60's) you could harm your valve SEATS, not seals.