If you live in an area that has fuel pumps that uses a single hoseand you have to select the octane fuel you would like,chances are,your paying for premium fuel you never get.
If the last guy fillshis tank withwith anything less than premiumunleaded and then you pull up and select premium, the fuel hose has to beemptied of regularunleaded before the premium fuel makesit to your tank. Not a big deal if you pump up your car with 10+ gallons butin my case I may only putin 2 gallons in mySportster...who knows how much of it is actually premium fuel.
What brought this up is the problem with my 2007 sportster pinging under load on the highway.. sometimes it was there other times it wasn't. I began using an octane booster and the problem has resided, so this prompted me to look at why the pinging was happening.

 

You're right...I don't know how much residual fuel is in the hose between the delivery valve and the nozzle, but if you are only buying two gallons, it would be enough to make a difference.

Another thing to think about is that not very many people use premium fuel, especially so in a rural environment, so it may have been in the storage tank a long time, gaining moisture and mold and who knows what else.

It would be very easy for Harley to deliver engines that run on standard 87 octane, and I have often wondered why they don't. I think it is a "image" thing, premium fuel for a premium machine. It sells bikes. Not very many people would notice any difference in performance with a tad less compression and a knock sensor that retards timing when detonation (knock) happens. This is SOP on automobiles now and not rocket science any more. No more ping problems, no more finding clean premium fuel problems either.

 

Running an air cooled engine on regular, especially withthe lean conditions to meet EPA requirements would tax the best technology known today. It could be done, but retarding the timing every time the engine got to the threshold where pinging would begin would create flat spots in the performance that would easily be felt in the seat of the pants. When you are dealing with a 150hp auto, losing a few hp to accomplish this is not a big deal, but a 65hp engine losing some ponies would be felt everytime it happened. I think that eventually HD must go the way of the metrics, water cooling to control the variables. Until this happens, I will happily put premium in my bike and ride it like hell

 

A friend of mine has a gas station in their family. He said you get up to 1 gallon of fuel befoe your selection pumps. He said to ALWAYS go to a pump that has separate hoses. I know that is impossible to always do. I just thought I would share what he said.

I have no way to verify his statement - but it is believable.

 

With the single hose gas pump, all grades of fuelleave their storage tanks and then cometogether into a manifold inside the pump,it'sthendispensed bya single hose.Provisionsare made for a 0.3 gallon flush before the state inspectorstake a sampleof fuel for quality testing.So yes, on a single hose gas pump, you are getting at least 0.3 gallon of whatever grade was last pumped. Multi hose pumps are the way to go.

DJK

 

just be nice guy and let your buddy get his gas first, then get your gas after him. (problem soled )