Fuel

[vechorik1373]

Do NOT use ethanol fuels, except when you are are out of gas and have no choice. Then drain it out when you get home and put it in your modern car.
Any machine with a carburetor (including our motorcycles) will develop carb problems. Ethanol LOVES water. It will even draw and combine with water vapor in the air. While it is mixed in gas, water will be present, bound to the ethanol. Over time, the water attacks the pot metal float bowls, corroding them, and eventually it will eat a hole through the pot metal. That will pretty much be the end of that carb body. I have seen it many, many times. The presence of water will also corrode BRASS.
The idle jet will be the first effected, and the orifice will slowly close and then be plugged solid.

And for those of you who do not know, go to this site. It currently lists 16,764 stations in the US that sells REAL gas:

https://www.pure-gas.org/

[Goro F]

I share what i know here in Italy since a type of gasoline is not anymore available in the market since years.

The gasoline was with lead, which was used to increase the number of octane. It was detonating agent. The fact that this is not anymore used could cause unwanted denotaning phenomena on old motors and damage them. I don't know how could be mitigated this risk.

But in addition to that, the fact that the today gasoline does not have any lead inside also make the gasoline much more "dry", since the lubrication effect of the lead is missing. For this reason it is strongly reccomended to use some additives to put in the tank once you fill it, to protect the engine (especially the valves) from the wearing.

Mosè

[niall4473]

Good advice from Vech.
However, here in the UK the last E0 petrol (gas) available, ESSO Synergy 99 has now been re-specified and is E5, a couple of other premium brands are still E5 but everything else is E10.
I only run one bike through the winter, the others I drain the carbs and tanks, but I still worry, given the cost and scarcity of serviceable caburettors for our machines.
I believe that Brazil has been using high percentages of Ethanol since the 1970s, are there any old BMW enthusiasts there who could tell us how they manage, and how did they get on with all those millions of air-cooled VWs?

[808Airhead]

I run my 4 on a mix of both. I always run the carbs dry before shutting them off. The trick is to ride them! And often! My bikes don't sit longer than 3-4 weeks at a time then get ridden, I "rotate" them ,and keep them running/driving and no problems.

[Daves79x]

Good points from all. My take is that you should by all means run non-ethanol fuel if you can (I'm lucky and it's readily available near me). But if you can't, the bikes will run fine with 10% ethanol, perhaps with a bit richer carb settings, but will run fine. The problem is once you shut it off - ethanol fuel just absolutely cannot sit in these carbs for very long (a few days), and I would never store one with even a full tank of ethanol gas. Drain the tank and carbs for the winter if real gas is not available. Stabilizers are largely snake oil. A full tank of unstabilized, non-ethanol fuel will last well over a year and still be fine.

Dave

[Flx48]

What fuel I should be using for my 1965 R50/2? I non-ethanal best? Or the high octane?

Hi Steve-
Adding to your collection of fuel thoughts, here in New England the climate is often characterized as a temperate jungle, because there is high humidity a good deal of the time.
And back when ethanol fuels first showed up around here, (maybe '06 or '07?) it quickly became apparent that E10 was hard on carbureted engines.
The folks making their living with carbed engines (lawn mowers, brush cutters, loggers, and the like) were the front line of the learning curve, because they had to deal with the effects of using the E10 fuel day in and day out.

They started out having to do multiple carb rebuilds on their machines annually, then they moved on to using the different fuel additives, and then finally settled on using just the hi-test E10, which appeared to remain stable longer, and augmented that with transferring any gas in their storage containers older than 3-4 weeks to their fuel injected trucks, which seem up to the task of digesting any stale E10 without issue.

Because ethanol is both hydrophilic (attracted to water) and volatile, (easily evaporates) what was learned was to purchase fuel from high volume service stations, which have to get frequent deliveries, and so have the freshest fuel.
The ethanol and the gasoline base are mixed together at the supply terminal, as it is being loaded aboard the tanker that delivers to the service station, and so at that point begins the evaporation of volatiles and absorption of water.

As Kurt pointed out, hi-test E10 will not produce more power in a low compression engine, but what the chainsaw guys discovered is that hi-test fuel is blended to remain stable longer; the reason for that is to prevent pre-ignition when used in a high compression engine, which also means that it resists vaporizing longer at normal atmospheric pressure, and so will remain stable somewhat longer.
The tradeoff is probably getting less mileage than the hi-test could get in a high compression engine (69S riders rejoice..)

When adding hi-test at the pump I try to follow someone who's just filled up with hi-test, as the hose itself may hold 3/4 of a gallon or more, not an insignificant amount for a bike tank.

As Vech pointed out, ethanol is also hydrophilic, (attracted to water) and the mixture of the two will produce a corrosive acid detrimental to metal it comes in contact with.
Our bikes need to use a vented gas cap, and so are susceptible to water vapor condensing on the inside walls of the tank, and so keeping the tank topped up is helpful in that it provides less surface area for water vapor condensation.
I store my bikes in a non-heated space in the off season, and so fill up with non-ethanol gas to winter over.
Whenever work or play takes me to nearby upstate NY, I bring along 5gal gas cans and fill up at Stewart's Shops (7/11 type stores) as along with E10 regular and mid-grade, they sell non-ethanol hi-test at around $5/gal.

I found Vech's link to pure-gas to be accurate for availability in my area, so probably good for other areas as well; my problem with its usefulness is that 15 of the 20 listings for my state were for Sunoco Optima (like Jim found) or VP Racing gas, both of which sell for $20-$25/gal, while the other 5 were marinas selling for $7-$8/gal, all pricing I cannot currently justify.

So my takeaway is the climate your bike lives in, coupled with how often the bike is ridden, is paramount to how concerned you may want to be about the effects of your fuel choice.
Best-
George