Little known history of the GL1000

By Pistol Pete Boody (RIP)
© 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 GL’s 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 0.5 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.