Concerns About Getting a Mix of Lower Octane Fuel

[Norbert]

Here's an interesting article from the WSJ. I never thought about getting the gasoline from the customer who was last at the pump. I guess if it was a big problem, we'd have heard about it by now. Still, it's interesting.

Does Fuel Get Left in the Gas Pump Hose?
Concerns About Getting a Mix of Lower Octane Fuel

Q: I ride a motorcycle with a typical three to four gallon gas tank. I ride where fuel stations are farther apart, so I fill up when the tank is still half full. The bike requires premium fuel, and doesn't run well on lower octanes. If the previous customer was pumping regular fuel, I assume the refueling hose is still full of regular fuel, perhaps a couple of gallons. This would mean I'm initially getting a mix instead of pure premium fuel. Is this a genuine concern, or does the system have a mechanism for evacuating the gas pump hose between uses?
-- Paul Kowacki,
Orange Mass.

A: It is a genuine concern, but one that motorcyclists tend to appreciate more than car drivers. According to the American Petroleum Institute the gas-pump hose typically retains about one third of a gallon of fuel. So when you pump a couple gallons of 93-octane premium after the previous customer pumped 87-octane regular, your fuel load would be diluted (not to mention overpriced).

This is more important to motorcyclists because bikes have smaller fuel tanks and a lower tolerance for low-octane gas compared with most cars. I have found that high-performance motorcycles designed to burn premium fuel run poorly on regular. They generally do not have the complex engine-control systems that allow cars to run on fuels of varying octane ratings.

I don't think diluting your premium fuel with a little regular will harm your motorcycle, especially if you always select the highest octane rating available. However, next time you're filling up you may want to get in line behind the driver with the highest-performance car in the station.

The link is here: Does Fuel Get Left in the Pump Hose? - WSJ.com
(Paid reg required, but I copy+pasted it here)

 

[racerws]

It's true you can get diluted octane fuel from the leftover in the gas
hose. However our FZ6 bikes can run on regular gas with no engine damage.
I usually put Premium or Midgrade as I think they are filtered and have
cleaners like Techron in them. For the small difference it makes
in the cost of a fillup, what the heck?

 

[Stumbles06]

Down here in Oz, every fuel pump has a hose for each different blend... eg. Most pumps here will have 3 hoses conected, 1 for regular, 1 for premium, and 1 for ethanol/petrol mix.

You guys only have 1 hose on the pump and then it pumps whatever blend you choose???
That just seems wrong to me.

 

[reiobard]

yup one hose and then buttons to select the blend. I would not be too worried about it since i run "low" test in my bike anyway, but i had never though of the mixing.

 

[bmccrary]

Down here in Oz, every fuel pump has a hose for each different blend... eg. Most pumps here will have 3 hoses conected, 1 for regular, 1 for premium, and 1 for ethanol/petrol mix.

You guys only have 1 hose on the pump and then it pumps whatever blend you choose???
That just seems wrong to me.

At most pumps it is that way, however there are still some companies that have 2 or 3 hoses. If its a two hose deal, then 87 and 89 is combined and 93 has its own. Pumps that have race gas, ie 100 octane, always have seperate hoses.

For the most part I have found that BP stations tend to have a hose per grade.

-bryan

 

[Ghost Weim]

Down here in Oz, every fuel pump has a hose for each different blend... eg. Most pumps here will have 3 hoses conected, 1 for regular, 1 for premium, and 1 for ethanol/petrol mix.

You guys only have 1 hose on the pump and then it pumps whatever blend you choose???
That just seems wrong to me.

Very interesting on the original post - I guess it never crossed my mind.

I will have to make sure that I stop at the 2 or 3 hose pumps from now on.

 

[bmccrary]

The only issue with the multi hose deal is that not all of the fuel leaves the hose. So if you were trying to fill up on premium and the last user got 87, then the first half gallon or so will be 87, or however much was left in the lines after the switch.

Its really no big deal, some people will make a bigger deal out of it than it needs to be. Some of the guys around here at school with high number cars complain about this situation.

-bryan

 

[wolfc70]

This is usually not a problem with most motorcycles as a 2-5 gallon fill up will negate any fuel left over in the hose. On scooter/mopeds it is more of a concern. My Honda C70 Passport only holds .8 gal, so this is an issue for me. I try and visit pumps that have a separate hose to fill up the c70. Unfortunately, as stations remodel, the single hose variety seems to be winning. So I refill at home with a 5 gal gas can. A pain, but at least I know I am getting the correct octane.

 

[IceCarver]

tell me this I have access to 100 octane I want to fill up with this being that I can tell a massive difference between reg and premium I dont want to over do it though is it alright to fill up with 100 or should I be content with premium




4 nuts dont belong on two wheels

 

[DefyInertia]

tell me this I have access to 100 octane I want to fill up with this being that I can tell a massive difference between reg and premium I dont want to over do it though is it alright to fill up with 100 or should I be content with premium




4 nuts dont belong on two wheels

whaaaat?

 

[mabbott]

It's true you can get diluted octane fuel from the leftover in the gas
hose. However our FZ6 bikes can run on regular gas with no engine damage.
I usually put Premium or Midgrade as I think they are filtered and have
cleaners like Techron in them. For the small difference it makes
in the cost of a fillup, what the heck?

Where are you getting your information from? I believe the owners manual requires a minimum of 89 or 90 octane for the FZ6. Please correct me if I am wrong as I do not have my manual with me.

 

[alanrim]

They would never get away with that in UK, trading standards would shut them down.

You could be paying for a lower grade fuel at the higher grade price, let alone the fact you are putting it in your tank.

 

[VEGASRIDER]

Where are you getting your information from? I believe the owners manual requires a minimum of 89 or 90 octane for the FZ6. Please correct me if I am wrong as I do not have my manual with me.

Okay, you,re wrong. Our FZ6's our desiged to take regular 87 octane, which is stated in the owners manual. I have put both premium and regular and have noticed no difference in performance, just the wallet.

On another note regarding the pumps, the pumps around Vegas has four, regular, mid-grade, premium, and diesel. No fuel contamination around here.

 

[wolfc70]

tell me this I have access to 100 octane I want to fill up with this being that I can tell a massive difference between reg and premium I dont want to over do it though is it alright to fill up with 100 or should I be content with premium




4 nuts dont belong on two wheels

RON = Research Octane Number is tested in variable compression engines on a test bench, and is the standard octane rating in Europe.

MON = Motor Octane Number or aviation lean octane rating uses an engine under load, and is better at determining how fuel is under load. This uses a preheated mixture and higher engine speeds than the RON. Usually 8-10 points below RON.

AKI = Anti Knock Index, also known as, pump octane, uses the average of the MON & RON (R+M/2) to get the number. This is the standard for octane ratings in the USA. All pumps will display the (R+M/2) under the octane number on the sticker. AKI numbers are about 4-5 points below the RON number. That is why 87 AKI is fine to use in the FZ6, as it is about the equivalent to a 91 RON rating.

The higher the octane number, the slower the fuel burns. If your bike is running fine on 87 AKI, running 100 AKI will actually decrease your performance. On a very hot humid day if you hear pinging, switching to a 89 or 91 will help, otherwise just plain old regular 87 AKI will work fine for just about 99.9% of street riding. However, do not run an octane rating below 87 AKI, as the FZ6 has no form of knock sensors, detonation/preignition will occur and damage your engine.