Fri Sep 20 23:49:44 1996 - Message No. 10
From: "Onno van Schelven"

Subject: RE: Fuel quality



Hi from Paris
Stefan wrote:
"A question from me to all of u: What kind of fuel do u use?????????

Hello again to you all,

Regarding the leaded fuel. The straight answer is that your Africa Twin will
run fine on the cheapest regular fuel you can find.

YOU DON'T NEED LEADED FUEL AND YOU SHOULD NOT USE IT, BECAUSE IT THREATENS OUR
HEALTH.

Lead was added in the stone-ages to improve the "knocking"-resistance of fuel.
Knocking is a very destructive phenomenon, where the fuel-air mixture burns
spontaneously before it is ignited by the spark plugs. It will make itself
known by a very awesome sound coming from your engine, especially when you
pull out of low engine revolutions. It is as if you drive a very primitive
tractor. The phenomenon is in fact similar to what is supposed to happen
within a diesel engine (self-ignition), but not in a controlled way.
This problem occurred with the rising of the compression ratio within the
cylinders of our engines, because we wanted more power from them. The
"octane"-number relates to the knocking resistance. In Western Europe regular
fuel has a knocking resistance of Octane = 95. The leaded fuels usually have
an octane = 98. In Russia you will be able to find fuel with an octane of 85
(= a relatively low knocking resistance).

In medieval times lead was sold by the gasoline companies as a kind of
lubricant as well, protecting the surface of your pistons, valves, valve stems
etc.

In the last 20 years all engine producers turned away from lead additives,
because of the environmental consequences (lead is poison and builds up in the
eco-system). In some cases lead can be harmful to engines, more particularly
for fuel injection systems, sensors in the exhaust system and catalysators.

The engine builders who kept building engines for leaded fuel was Austin for
its Metro (who else).

The reason that leaded fuel is still available is that there are still cars
and motorcycles around who need it.

Our Africa Twin was designed as a endurance traveler, being able to face the
most primitive situations the world will provide. So, the Honda engineers kept
the compression ration to a very modest level (unless you tuned it) and the
engine will almost run on everything. My latest experiment was fuel
contaminated with diesel, because I drove the tank clean empty and it was the
only thing available in a nearby farm. The engine run fine, although with a
bit more black smoke than usual.

The latest trend is that leaded fuel is being replaced at the gas stations by
a new type of fuel, without lead, where the lead is replaced by another octane
improving additive, usually a alcohol derivate.

Stand on your footsteps!!

Bye, Onno


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