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poppygene wrote:

High_Side wrote:

oldnslo wrote:If you want a long, dry, technical explanation, I can provide it, but the short version is that if your bike runs well on 87, don't bother wasting your money on anything higher.

Thats what I thought until I discovered the increase in mileage......

Interesting. My bike runs just fine on 87, mild compression and all (8.7 to 1). I'll have to see if I get a similar increase in fuel economy. The ol' girl is really thirsty - not exactly a cheap date.

I found that the biggest bonus was being able to make it to another town before filling up....or in the case of the VTR, making to any town before running out!

The higher octane seems to make a big difference in mileage with our pickup truck, it costs more for the gas but it definatly goes further and runs smoother.

I always try to use the same gas in my Buell and its a 94 Octane, I get 50-65 MPG, so for what it costs, I use the good stuff.

Buelligan wrote:The higher octane seems to make a big difference in mileage with our pickup truck, it costs more for the gas but it definatly goes further and runs smoother.

and the further part is part of what might make it worth it...

when i drove across the country, i got to burn through plenty of tanks of gas, and discovered that i usually got an extra 20-30 miles on a tank of 91+ than on 87. that was about the equivilant of another gallon and a half of 87 in the car i was driving ('86 Saab 900 SPG loaded with all my worldly posessions), which at the time meant i came about even in cost, with the added security of being able to make it to the next gas station (because there are some points along the I40 and Route 66 where you can go very long distances without seeing another gas station, and you'd kill for that extra 20-30 miles).

it really just depends on the engine; burn a tank in premium and regular and see how it works. calculate your mileage and see how the bike/car feels.

Might be some of that regular out there in the midwest and elsewhere has a higher ratio of alcohol, which reduces gas mileage. I don't know if premium is watered down with alky or not. I do know that premium is about 40 cents a gallon higher around here.
What the heck, it's only money, do what you are comfortable with.
This topic seems to be even more contentious than motor oil, and we all know your bike will blow up if you use car oil in it.

Just to throw in my - My 84 FJ 600 is 10:1 compression, and calls for premium.(91 or higher) I've been told though that it will run fine on regular.(87) I hesitate to try it though, so I compromise and run the mid-grade 89 octane. So far it runs fine, no pinging and I get from 45 to 52 MPG depending on how hard I ride.

oldnslo wrote:... more contentious than motor oil, and we all know your bike will blow up if you use car oil in it.

You kill me!

Now really friends , when you stop to think about it , most of our tanks are somewhere between 3 & 5 Gallons so all we are talking about here is 60 cents to a dollar total cost overide ...........by running premium .
And imnsho , it is much kinder on your scoot .
Kind regards, Wizzard

Unfortunately, that is simply not the case with older bikes. I can tell you from experience, that premium causes poor performance in my bike. No point in going round and round about it. It happens every single time, so I stopped using it. BTW, the price is the same at the station I use, so there's no reason to think people aren't using it...It's not just bad gas. Old-n-slo is right about the technical explanation, but it can be proven by asking this question on a vintage bike site like kzrider.com.

I'm not trying to be a jerk or anything, but sweeping generalizations can lead to frustration for readers seeking accurate information, so... Follow the owners/service manual, and you'll hit it on the head, every time.

My Mean Streak requires 91 octane or better (high compression and a hot cam), despite the water cooling and dual plugs per cylinder. My dad's C50, on the other hand, recommends anything >87 octane. The reason a lot of cars are able to run on 87-octane fuel is because their electronics are more sophisticated (more sensors) and the engine management system is able to advance and mentally challenged the spark much better. My Chevy Colorado only requires 87-octane, but I have noticed a significant increase in power since trying 93-octane. Bikes only hold maybe four or five gallons of gas, and get hella good gas mileage, so paying extra for premium shouldn't break anyone's bank, especially Harley riders (you've already paid twice what the bike is worth just for the name) so don't skimp at the pump unless your bike specifically states that it'll run on the fuel you've chosen. Detonation will destroy an engine in short order.

ronboskz650sr wrote:Unfortunately, that is simply not the case with older bikes. I can tell you from experience, that premium causes poor performance in my bike. No point in going round and round about it. It happens every single time, so I stopped using it. BTW, the price is the same at the station I use, so there's no reason to think people aren't using it...It's not just bad gas. Old-n-slo is right about the technical explanation, but it can be proven by asking this question on a vintage bike site like kzrider.com.

I'm not trying to be a jerk or anything, but sweeping generalizations can lead to frustration for readers seeking accurate information, so... Follow the owners/service manual, and you'll hit it on the head, every time.

Bikes are not cars...John, can you hear my head hitting this wall?