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Post by xsyamahadg on May 1, 2008 19:23:41 GMT -5
Which octane rating do you use in your bike ? My bike calls for a minimum of 87, but I use an 89 rating at Marathon. I'm not sure it pays in performance to use a higher octane rating than is recommended, but I don't think it hurts to bump up one notch.
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Post by thundercloud on May 1, 2008 19:56:27 GMT -5
Mine also calls for 87,tried higher but no difference in performance or mileage. Two up 54mpg. I can live with that.
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Post by Deleted on May 1, 2008 20:03:22 GMT -5
Sunoco 94+ or nuttin
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Post by Jennifer on May 1, 2008 21:00:13 GMT -5
Gimme the cheap stuff... I refuse to buy anything (car or bike) that requires premium fuel...
It's just really sad that it's cheaper to drive my car than ride my motorcycle... it just seems wrong!
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Post by bill on May 2, 2008 0:31:41 GMT -5
Over here all we have is 95 unleaded or diesel, shell do a higher octane and we are now seeing Bio Fuels making an impact on the forecourts.
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Post by 87fxlr on May 2, 2008 6:59:42 GMT -5
Sunoco super 94 if I can get it. Other wise I try to buy more of a name brand type BP, Shell. I try to steer clear of those that add ethanol to their gas. I'd much rather pay through the nose for all gas than pay through the nose for 10% of what would have been corn liquor.
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Post by jeffe on May 2, 2008 7:34:18 GMT -5
Not trying to start a big controversy but.........If I remember my high school chemistry correctly, the octane rating in a round about way only determines how easily a substance burns. The lower the rating the easier it burns. Now if I remember what some of my old long lost Hot Rod magazines said...Your engine will produce it's peak power at the lowest octane rating you can run with out pre-ignition or "pinging". This being said ...running a too high of an octane rating can actually make your engine be less efficient because it is not getting a quick, clean burn of the fuel. So what does all this really mean? If it pings run higher octane, if it doesn't run what fits your wallet. Unless your engine really needs a high octane the benefit of running a higher grade of gas is that it usually has more detergents and additive to help keep your engine clean, this last bit is from my dad who was a bulk fuel distributer. I remembered all this but does anyone know where I parked my bike?
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Post by tamarack on May 2, 2008 7:35:44 GMT -5
Mine calls for 87 and that's what I use. I've done some research on using higher octane then what is required. I used to think that using higher octane could only help, if even a little. Turns out not only does it not give you any advantage in either mileage or performance but it can hurt the bike. It seems that the higher the octane the hotter (more complete?) it burns. So, if your bike isn't designed for the higher octane it could even hurt by possibly burning your piston.
The higher octane is really just an "anti-ping" fuel. So the higher the compression on your bike the "hotter" the burn has to be to drive the piston properly. That's why if you require high octane, and you use low, the engine will knock and ping.
Of course I've described this in layman's terms but there is plenty of technical info out there on this subject. Before I knew the above I also thought higher octane = more power and I have tried it but also did not notice any increase in performance or mileage.
I also try to use "name brand" gas whenever possible due to the additives used in the fuels that help keep the engine cleaner. I've heard people argue (and I once felt the same) that you see a tanker leave a supply depot and go to the BP and then go across the street to Joe's Cheap Gas. So, one would think it's the same gas. However, the additives are often added at the station. They can also be added at the depot. If additives are added at the supply depot, one section of the tanker may have the gas for BP with the additives and one section may have the gas for Joe's without.
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Post by xsyamahadg on May 2, 2008 8:25:12 GMT -5
One of my experiences with high octane gas proved Jeffe and Tamarack's point completely. My old XS650 calls for 89 octane rating, but since it had been sitting for a while, I ran a tank of 93 octane thru it to clean the carbon and cobwebs out. The end result was a pair of spark plugs that were burning bright white instead of the desired chocolate brown color. Anyone who knows air cooled bikes, knows that a bright white spark plug means a lean burn situation and the engine is in danger of holeing a piston. The next tank of 89 octane produced the chocolate brown spark plug reading that I like to see. My deduction from all of this is that the higher octane gas can produce a lean burning engine with low compression engines.
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Post by jeffe on May 2, 2008 9:24:03 GMT -5
A funny story relating to octane. Years ago when I believe Sohio came out with their high octane gas a friend was convinced it was the best thing ever and would double your HP. He kept after me to use it in my SR500. I kept telling him that that bike would probably run on about anything that you could get into the tank. He kept after me to use it and even offered to fill up the tank for me. Free gas...go ahead. We were out riding right after he filled the tank for me and I did a big dummy and went down. No damage to the bike... just my pride hurt. As another friend and I were picking the bike up I looked at the free gas friend and dead panned" You know why I wrecked? As I was going around the corner a slug of that new gas musta hit the carbs and with all the extra HP I lost control and wrecked." He responded very seriously."I told you that might happen. Maybe you'll believe me the next time." My friend who was helping me pick up my bike starting laughing so hard that we dropped the bike and did the only damage that occurred, a broken turn signal.
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Post by mgorman on May 2, 2008 9:59:02 GMT -5
I did some field testing on this Octane thing. As mentioned before and from my own research High octane resists burning and burns slower. Low Octane burns fast and ignites easier.
I used a '99 XR250R that will run on anything that you can light with a spark. I took a tank of 93 octane and a tank of 87 octane. I drained and refilled the bike for each can. The bike ran very noticably better on the cheaper low octane fuel. The same thing was done to the Transalp and it also runs much better on cheap stuff.
I have been running the cheapest gas I can find since 1989 in my transalp and it runs like a charm with 50,000 miles on it. The carbs have never had to be cleaned and no plugs have been damaged.
High octane resists burning and burns slower. If your motor is NOT high compression, it will not burn the gas cleanly. As mentioned before, if your motor doesn't knock or ping, your wasting your money. Think of the cheap stuff as unstable dynomite that will explode with ease. It burns fast and easy.
A bike like a CBR, Duc or Hyabusa may require high octane to keep the high compression motors from detonating. My KTM has a wiring harness that can be altered to allow for the use of 3rd world gas so I keep it unplugged and run cheap stuf through it too.
I'm not giving Bush or his cronies any more money than I have to.
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Post by jeffe on May 2, 2008 10:43:05 GMT -5
Just one further thought. During WWII the US had an advantage because we could produce very high octane aviation fuel. Somewhere around 110 to 120 octane. This allowed us to highly supercharge the aircraft engines and give them much higher performance. Germany had to result to complicated water/alcohol injection systems to allow their engines to have comparable performance. These systems help cool the intake charge so that the temp in the cylinder would be lower and have less of a chance of detonation. The US used similar system's, but not to the same extent.
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Post by 87fxlr on May 2, 2008 12:38:07 GMT -5
The Harley's call for high octane... Trish's pings and bangs and runs like crap without it.... Mine? With the pipes I have on there you really can't tell but the manual still calls for premium.
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Post by xsyamahadg on May 2, 2008 13:02:47 GMT -5
I think some of the Oldsmobile 4-4-2 high performance engines experimented with some form of water injection in the late 60s, I think they called it "Inter-Cooled". I could be wrong....I wasn't a big fan of the 4-4-2.
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Post by jeffe on May 2, 2008 13:49:37 GMT -5
We had a neighbor that had a large farm tractor that ran on propane. It had to use some form of water injection or it would cause engine damage. Also ,the early jet engines used a form of it also.
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