Little known history of the GL1000

By Pistol Pete

Little known history of the GL1000
By Pistol Pete Boody
© January 2005

Circa 1990 I began my research into the history of my 1975
Goldwing GL1000, Nellie-Bell. My discoveries were pretty cool
at best, but for the most part they were fairly common knowledge.
Honda has always had a reasonable means of keeping track of when
units were produced by recording the month and year of its
production on the nameplate that is located on the front of the
bike’s frame at the steering head. On most all of the early GLs
this plate is positioned to the left side of the head section.
The month and year of manufacture are recorded in the upper right
hand corner of the plate. Since all GL1000s were made in Japan,
and because the USDOT made no demands on changing it, Honda saw
no need to alter the way this plate was made or where it was displayed.
Another discovery was also no great revelation; there
were eleven prototype GLs made before the actual commercial
production units began.

Late in December of 2003 I had an opportunity to purchase yet
another 1975 GL1000, and because of this one purchase, I have
been able to use it and other ‘75 GLs as a portal in time.
These bikes have led me back to 1974. This particular Goldwing
looked, sounded, and acted just like my Nellie, but as I was soon
to discover, this was not a run-of-the-mill production Goldwing.
In the upper right corner of the nameplate was the revealing
“12/74.” I was completely amazed by this find, because I, like
thousands of other Goldwing owners, had thought that production
of the GL1000 had begun in January of 1975. But this one machine’s
manufacture date indicated that this was not true. Additional
research led me to the discovery that there were as many as fifty-
two GL1000s produced before January 1975. Excluding the eleven
prototypes, then, that leaves forty-one other bikes. I calculated
that most, if not all of these mysterious units were assembled in
December 1974 to early January 1975.

Remember that this was a time before computerized drafting (CAD)
or 100% proven methods of producing a product from day one. So
it came as no real surprise that Honda began its ascent into
full-scale production by making these pre-production GL1000s one
unit at a time and with the idea that each unit produced would
provide research needed to be able to go to high-speed production
in mid January 1975. This also gave them the perfect opportunity
to begin compilation of owner’s manuals and service manuals
(and probably in that order). Unlike Honda, several hundred
GL owner’s manuals of the early 1975s were printed with mistakes.
It is a rare find to locate one of these manuals, and unless your
‘75 bike has its original manual intact and it was made before
circa 2/75, you may have never seen one of these fantastic little
booklets. I remember receiving the stick-on page sheets from
American Honda Motors, which were to be placed over the manual
pages containing the errors for Nellie.

If you are very familiar with the mechanical parts of the 1975 model
Goldwing, you know that the carburetor butterfly actuator rods (linkage)
were made from aluminum castings. Each of these linkage rods employed
a spring-loaded attachment end that fit onto four ball-ended lever pins.
In 1976, Honda changed this design to sheet metal bars that used brass
bushings in place of the spring ends. This was done to make the operation
of the carburetor butterflies smoother and to keep them synchronized better.
The bars on the 12/74 units were made from billet material; i.e., they were
machined from solid aluminum10- or 12 mm square bars and were not cast.
Another interesting characteristic of my 12/74 unit is that on the right rod
Honda made an error when drilling the vent holes in the ends with the spring
mechanism. These holes appear facing upward and are in view. All other
production rods were corrected and the vent holes are on the underside of the rod.
This particular operating rod on all ’75 units is not universal and can only fit
one way.

I found other anomalies on this particular 12/74 bike. The nuts that hold the
muffler to the right and left bracket appear to be original to the bike but
they are 8 mm flange nuts, not the 8 mm plated cap nuts found in the later
production bikes. The water pump leaked when I purchased it and I carefully
replaced it. To my surprise, I found that the thermostat cover behind the
cooling fan motor had no o-ring groove, but was instead smoothly machined and
a flat gasket was fitted in place. I carefully fashioned a new gasket from .5 mm
gasket material and installed it at re-assembly. The water hose clamps are also
different than the production clamps used from January 1975 until 1977.
The 12/74 clamps have an in-turned flange on one side of the strap that allows
the clamp to slide onto the hose but only until it contacts this flange.
During disassembly of the front engine cover, I found that the left inside of
that cover was built up with weld. Apparently, the casting wall thickness was
substandard when cast and before machining it was welded to bring it to the
required thickness. I asked a Honda expert about this anomaly and he said that
this was extremely unusual for Honda to allow this to happen because of their
stringent inspection methods.

If you own a service manual published by the American Honda Motor Company, Inc.
(PN 6137101 HC 44382) for the 1975/1976 GL1000 (dated 1/76), you can find some
of the items that I discovered right there in the printed pictures. In section 8,
p. 10, top picture, you will see one of the water hose bands that I discussed.
In the bottom left picture of section 4, p. 6, you will see the gasket beneath
the thermostat cover. In both pictures in section 4, p. 9 you will see an earlier
prototype version of the billet linkage rod. Also in section 9, p. 18, the lower
picture shows the type of billet rod as placed on 12/74 units. Note that the center
portion has been turned on a lathe and is different looking than the production
cast finish.

Further discussions with the Honda guru has made me realize that these truly fabulous
machines from 1975 to 2005―the Honda Goldwing and all of its 30-year production history,
began with these pre-production units that were used to ultimately solve many production
questions. The Honda Goldwing is and will remain the one true touring machine of the
20th and 21st centuries.

In my humble opinion, at the center of every Goldwing ever made is the beating heart of
the 1975 GL1000.