mid versus premium grade fuel/startup

[R1150Rclean]

With Shell fuel, bike starts up fine with mid grade and full choke, but if I use premium I have to use the full choke AND twist the throttle a little. Have gone back and forth several tankfuls, and I get the same result. Is the higher octane in premium suppressing the ignition too much? Bike runs fine on both fuels.

[twindave]

I think the higher octane does suppress the volatility of the fuel or maybe it is the additives. I don't know for sure...I'm not a fuel expert. I just know what works and saves a few bucks too.

I use regular gas most of the time, and I rarely use the choke. It seems to do very well except for the real hot days.

In the cooler months, regular makes her run like a wild animal.

The only time I use premium is when I do a mixture of seafoam to clean out the gunk and rid her of pinging.

[boxermania]

The diference between the gasoline grades is in the additives, gasoline doesn't burn, it literally explodes, a portion of the additives goes to slowing the flame front hence the term "controlled explosion" which minimizes pinging/pre-ignition. The caloric value or energy content is the same accross the 87/89/91 pump ranges.

I live in the deep south, ran 89 in a modded bike and never experienced your problems. How is your state of tune, plugs, valve adjust, TB's sync, idle speed, air filter?

[CycleRob]

The most likely cause of hard starting with premium fuel is that the batch you're using is several months old and lost some of it's volatiles. It's the way it is in good times. With the economy down and stalled, fewer people are running premium fuel and they also are driving less. Unemployment adds to that.

BTW, It's not a "choke", it's just a fast idle lever.

[R1150Rclean]

The diference between the gasoline grades is in the additives, gasoline doesn't burn, it literally explodes, a portion of the additives goes to slowing the flame front hence the term "controlled explosion" which minimizes pinging/pre-ignition. The caloric value or energy content is the same accross the 87/89/91 pump ranges.

I live in the deep south, ran 89 in a modded bike and never experienced your problems. How is your state of tune, plugs, valve adjust, TB's sync, idle speed, air filter?

89 is good, it is the 91-93 that causes the problem. Everything is properly adjusted with a reasonably new air filter (2k miles on it).

[Sander Abernathy]

There's more misinformation on the premium vs. regular topic than truth so I hesitate to add to it since all I can do is parrot what I read somewhere else. High octane fuel has an intended purpose and that is to limit detonation. They accomplish that goal by making it harder to ignite or less volatile as someone else noted.

So premium makes starting more difficult under certain circumstances but it generally occurs when it is extremely cold. At normal temperatures, premium is sufficiently volatile to ignite readily. I don't know where you are but we aren't suffering from extreme cold here at the moment. Perhaps there is another problem. I wouldn't attribute it to premium gasoline right away because the difference between premium and mid-grade isn't enough to explain what you are experiencing.

I wouldn't worry about buying old gas. There isn't storage space in the US supply chain for gasoline to sit in a tank and grow old.

On the R1200R forum, some people are raving about a fuel additive that they claim has really improved their performance. Personally, I think fuel additives are bunk and when one is proven to provide any real advantage the refineries will simply add it to their product. However, the claims people are making would seem to indicate that it might help your problem.

Another possibility if the problem came up in the last few weeks is that the gasoline in your area is "summer blend". Summer blend is less volatile than gasoline sold at other times of the year and is federally mandated in markets with a lot of ozone. It evaporates more slowly so less escapes into the atmosphere to be converted into ozone. It is less likely to cause vapor lock in hot weather but more likely to cause difficulty starting the vehicle. Premium summer blend has two strikes against it compared to regular mid-grade. First it's premium and second, it's summer blend.

[iowabeakster]

I think Sander makes excellent points above.

But...

I must disagree with

I wouldn't worry about buying old gas. There isn't storage space in the US supply chain for gasoline to sit in a tank and grow old.

It's not the wholesale supply chain... it's the tank underneath the pump at the local gas station. Some gas stations that don't do a lot of buisness are a problem. Premium does not sell nearly as fast as the regular grade, and at some places it can sit in the underground tank for quite a while. I've definitely bought some bad gas on occasion, no question about it. This happens most, when the station has just got a load of fresh gas. All of the water that had settled at the bottom of tank in the previous weeks/months gets stirred up.

Stick to the stations that do good business, and it shouldn't be a problem.

[Sunbeemer]

+1 -> If I see a tanker truck at a gas station, I'll pass it up and ride to the next station. Water isn't the only stuff that gets stirred up from the bottoms of those tanks

[Sander Abernathy]

I said there isn't old gasoline in the supply chain. The response was "I know there is old gasoline in the supply chain because I got bad gasoline after a truck delivered fresh gasoline." I never said anything about bad gasoline. However, if a fresh fuel delivery stirs up sediment that causes your engine to run poorly, you can't blame old gasoline because the gasoline in your tank is fresh. It's just contaminated with water and sediment.

A couple of years ago I would have agreed with that there was old gasoline at low volume gas stations. Then Hurricane Katrina hit New Orleans. It impacted Atlanta, where I live, about three days later. The news broke that virtually all of Atlanta's gasoline comes through a pipe from southern Louisiana and with the wells not pumping and the refineries not refining, no gas was going into that pipe. That news hit on a weekday evening and by 8 am virtually every gas station in the metropolitan area was flat out of gas. That tells me that there is less capacity in the filling station tanks in your area than there is capacity in the vehicle tanks. If everyone fills up on the same day there isn't enough gas to go around.

I agree with the advice to fill up at stations that are busy because they won't have old gasoline.

I agree with the advice to never fill up if you see the tanker truck because when they add fuel it stirs up sediment and water from the bottom of the tank.

The problem is following both pieces of advice. A busy station gets a gas delivery every 24 to 48 hours and it takes hours for the water and sediment to return to the bottom of the tank. Whether you see a truck or not at a station, if it's busy there's a high probability that the tank hasn't settled since the last delivery.

As for the low volume convenience store, the retail margins on gasoline aren't enough for the owner of a low volume convenience store to carry more than a few days supply of gasoline so no one is buying more than a few days supply. Interest cost alone can consume the entire retail profit margin on gasoline in a few weeks. The point is that storing gasoline is generally a lose/lose proposition and as a result there is no storage capacity.

The scenario described above is known as contango and that is the normal state of a commodity market. A commodity market is typically in contango because the current price is greater than the future price because someone delivering the commodity in the future has to pay carrying costs. The opposite is backwardation which is when the current price of a commodity is less than the future price. When backwardation occurs, commodity traders may buy and store gasoline today and enter into contracts to deliver that gasoline at a higher price in the future.

Backwardation occurred in 2005 and 2006 with crude oil and investment banks were literally building oil storage tanks for themself and leasing tankers to sit idle and store oil.

There is surely bad gasoline but there is very little old gasoline.

[Sunbeemer]

Why shouldn't "backwardation" result in "bad" gas if it was being stored for future profit?

I've heard that ethanolated gasoline goes "bad" in as little as three weeks (which is probably dependent on blend and storage conditions). Here in hot & humid Florida if you don't put Stabil in a lawn mower or boat that doesn't get started for a month or more, it might not.

I have gotten tanks of bad gas resulting in a poor running engine, most memorably in TN last summer, but also from the premium pumps at local stations. Sometimes a shot of Seafoam in the tank helps.

[chibbert]

The diference between the gasoline grades is in the additives, gasoline doesn't burn, it literally explodes, a portion of the additives goes to slowing the flame front hence the term "controlled explosion" which minimizes pinging/pre-ignition. The caloric value or energy content is the same accross the 87/89/91 pump ranges.

This

[CycleRob]

With 10% Ethanol in practically all our gasoline now, ANY water in the tank before the tanker fills it WILL be absorbed by that swirling addition of new 18 wheeler tanker fuel. Add to that any residual water in every storage or train transport tank downstream from where the Ethanol was first added

You could easily buy gasoline that is 5+% water. Is it any wonder why it starts harder with gasoline from a different in ground tank?

You can thank the Greenies for borrowing Ethanol from the food supply chain and giving to us an inefficient, corrosive, inferior motor fuel.

.

[Sunbeemer]

No to mention what an utter waste it is to burn good ethanol rather than drink it!

[mcollect]

Cyclerob:

You can thank the Greenies for borrowing Ethanol from the food supply chain and giving to us an inefficient, corrosive, inferior motor fuel.

I believe this is the first time you are truly WRONG! The Greenies don't want corn taken out of the food chain and turned into ethanol. That my friend, was the elected folks from the corn producing states. The environmentalists know that the use of ethanol is an energy loss. This information comes from a director at Department of the Environment.

[chibbert]

Cyclerob:

You can thank the Greenies for borrowing Ethanol from the food supply chain and giving to us an inefficient, corrosive, inferior motor fuel.

I believe this is the first time you are truly WRONG! The Greenies don't want corn taken out of the food chain and turned into ethanol.

Although you may be right that the elected representatives are pushing this - sit and listen to nearly any tree hugger for a few minutes and you'll hear that they are for it (ethanol) too.

[NoRRmad]

I'm not for it. I'm for raising the tax on gasoline. I think I qualify as a "Greenie."

Ethanol is a perfectly good fuel, all things considered. If vehicles were designed for it, the problems we see wouldn't happen. Its only fault is that the BTU content per pound/fluid ounce isn't as high as gasoline, so fuel tanks would have to be bigger and sealed against moisture better.

And, of course it is more expensive to produce once you eliminate the subsidies.

This part of the discussion should probably be moved to Patrick's Playhouse, so we don't pollute the main part of this board with politics.

[chibbert]

I'm not trying to attack this from a political position. If we need to move to Pat's playground we can. It's just my understanding that if we moved to ethanol completely, there isn't (and can't be) enough corn to go around. Blending ethanol and petro-based fuels goes against the very purpose for ethanol in the first place unless the sole purpose is to make more money.

I always use premium in my bike and always use regular in my vehicle. The only think I have ever noticed when not using premium in the bike is pinging.