Motorcycle Forum / General / Motorcycles / July 2007

I attended an "Open House"(aka ride any/all the bikes
you want) at a local dealer, where I selected a GW.

Without any preconceived opinions, I noticed this sur-
ging that you describe, when I stopped at signals. I
suspect the bike I was allocated was probably an '06.

Sorry, can't speak to (ab)normal, but I'd suggest you
join-up/hang-out over on one/more of the GW owner
group sites. When it comes to technical information,
bike discussion, recall notice, and even class action
lawsuits, they're the greatest.

Here's a few of which I'm aware:

http://www.gl1800.org/
http://www.gwrra.org/
http://www.gwrra-tx.org/

The texas link may be outside your region, but I'm sure
all are welcome.

You have two oxygen sensors. The PGM-FI runs in the closed loop mode when the
engine is warmed up. The PGM-FI "listens" to what the oxygen sensors are
telling it.

Oxygen sensors don't put out a continuously variable voltage when responding
to the temperature changes in the exhaust pipe caused by rich or lean
conditions.

They put out a very low voltage of about 0.1 volts or a "high" voltage that
is still less than 1 volt.

Digital circuitry, like in the PGM-FI, use high/low voltages anyway.

This problem might have to do with the oxygen sensors "firing" as a rich
condition occurs in the exhaust pipes. The PGM-FI then causes the air
injection system to send a slug of cold air to the exhaust port to burn off
the excess hydrocarbons, and the oxygen sensor then cools down, the PGM-FI
recomputes how much injector time is needed for the new consitions, and the
fuel injectors stay "ON" for more milliseconds.

So you get surging as the oxygen sensors heat up and cool down.

Anyway, that's my theory...

My '03 does no such thing.

Never noticed any surging whatsoever on my 06.

Willy