NEWSLETTER October 2024: GL1000 Report
In the summer of 2023, noted British moto-journalist Alan Cathcart paid a second visit to RetroTours, accompanied by photographer Kel Edge. Alan rode 7 bikes from the RetroTours fleet, including the GL1000. Here is a translated excerpt from his article which appeared in a Czechian E-magazine. You can read the article in its entirety by clicking on this link: https://motorkari.cz/a/y4p . You may need to copy the link and paste it to your search bar. Ask Google to translate it for you if your Czechian is a bit rusty. Helping Alan and Kel with the project was greatly entertaining. I hope you enjoy reading Alan’s work as much as I do.
By Alan Cathcart:
In December 1972, Honda assembled a team of its best engineers, led by Soichiro Irimajiri, who had led the development of Honda's four-, five- and six-cylinder GP racing engines in the 1960s. This team was tasked by Honda's top management to develop the so-called King of Motorcycles, in which the then largest motorcycle manufacturer in the world would boast of its technical prowess. The prototype, referred to as the M1, was born out of an ambition to impress, not as a result of targeting certain groups or according to marketing studies. The M1 was supposed to be a fast, comfortable GT model, surpassing
all other motorcycles in its finesse, performance and quality. To create extreme positions, the top-secret M1 prototype was powered by a liquid-cooled flat-six engine with a capacity of 1470cm3 with a drive shaft, which would also be used in the production version in the future. The official goal was a very
compact and lightweight motorcycle that would have extremely high performance by the standards of its time. The planned weight was 210 kg and the power of 61 hp at 7500 rpm, the maximum torque was high at 5500. The time in the 400-metre sprint spoke for itself, 12.40 seconds was a better result than the CB750 superbike at the time.
As soon as the M1 was created for review (remember, it was a top secret project), it was immediately decided to make a production motorcycle for general sale according to this concept. However, Mr. Honda himself, who was about to retire from the company he had created, still preferred air cooling for its simplicity and was convinced that engines with a capacity of over 750cm3 would be rejected by the public as too big, especially if they had six cylinders. M1 liquid cooling was a very radical idea at Honda at the time, but the brand's engineers knew that the operating temperature of air-cooled units depended on the air temperature. And that was unacceptable: the M1 had to drive controllably and reliably at the highest speeds and loads even in the hottest weather. And that was only possible with liquid cooling.Thanks to its exceptionally low center of gravity, the prototype felt lighter than the claimed 210 kg. Although it was actually a by-product of the layout, this feature was very popular with all testers and eventually became the focus of the whole design, because thanks to it the bike was able to take its weight very practically. The engine's designers were not bound by traditionalist biker thinking and quickly modified their design by placing the gearbox under the engine instead of behind it, and this innovation made the six-cylinder engine slender between the rider's shins, with all controls within easy
reach. This innovative thinking has also placed a 19-litre tank under the seat. For the future of motorcycles in general, the M1 paved the way for the universal acceptance of mostly maintenance-free, liquid-cooled engines in motorcycles of all categories. But before that, she had to pass a test at the
highest level. Legend has it that one evening Mr. Honda himself showed up in the R&D department of the test center. When he saw what its designers had created, he said with his characteristic directness that "it looks like a bat", due to the two blocks of horizontally opposed cylinders. He sat on the big machine, started it and drove off into the darkness. Soon he returned, parked, said it was "pretty good", and went home. Ufff!
The entire "pregnancy period" of the original four-cylinder GL1000 lasted just two years, from concept to production piece, given what the development team learned in the M1. However, when this bike was unveiled at the IFMA 1974 trade fair in Cologne, few people understood what it was actually looking at. In terms of straight-line speed, the new Honda was surpassed only by the Kawasaki Z1, the best
superbike of the Ɵme, and the GL's performance peaked at high revs. However, to be considered a hyperbike, the GL was considered too heavy, too long and too wide. Despite the slow start of sales, long-distance travelers gradually began to discover the stellar qualities of the GL, who tried different alternatives and discovered the machine of their heart in the GL. Owners soon discovered that the new
Gold Wing could carry all the baggage they needed for long journeys, plus a passenger, all in comfort and with Honda's already proven reliability to keep them from being stranded far from home.
The liquid-cooled flat-four engine with two valves in each combustion chamber had a perfect primary balance, and the counter-rotating alternator tamed the response of the 180° longitudinal crankshaft when you hit the gas. The camshafts, one in each cylinder row, were driven by silent toothed belts, as in the Moto Morini 3 1/2, which brought this solution to the racetrack in 1973. A bore of 72 mm and a stroke of 61.4 mm meant a displacement of 999cm3 and with a compression ratio of 9.2:1, the engine in production form produced 56.9 kW/78 hp at 7500 rpm, with a torque of 83 Nm at 5500. These were values comparable to the Kawa Z1 and its 81 hp/73.5 Nm. A quartet of 32 mm Keihin constant velocity
carburetors fed the engine from a primitive airbox. Fuel injection was considered, but in the end, it was rejected because it would still need further development for motorcycle purposes. The five-speed gearbox found its place under the engine and for the first time ever a drive shaft was used as a secondary transmission on a Japanese motorcycle. The engine housed a tubular double cradle frame, the 37 mm Showa front forks forming a 28° vertical angle offered 123 mm of travel and held a 19" wheel with 120 mm trail. The rear 17" axle was 1545 mm away from the front one, which gave plenty of room for a passenger, and a pair of shock absorbers gave the rear wheel 84 mm of travel, but in the first year of the K0, the shock absorbers had a relatively short life and soon owners replaced them with aftermarket replacements, most often Koni. A pair of 276mm Nissin steel discs with two-piston calipers worked adequately in the dry, but in the wet their effect was deadly – the owners even wrote a petition for Honda to do something about it! The single-piston 294mm rear disc was larger than the front discs, which was based on the fact that most Americans of the time (and especially H-D riders) preferred rear brakes. I guess it was their dirttrack heritage. With a claimed 583 pounds dry, the GL1000 was no featherweight, however, thanks to the weight being at the very bottom, you didn't notice it too much and it was good for handling on bumps when driving at high speeds. Although Honda's engineers
focused mainly on tuning the power in the midrange, the first generaƟon of the Gold Wing extracted surprisingly sparkling performance. Magazines spoke of a quarter-mile run in 12.92 seconds (there were not many attempts, the clutch soon gave up) with a finish speed of 104.52 mph (168.2 km/h), which was only slightly slower than the Kawasaki Z1. The top speed of 208 km/h was also very good, you just needed a longer start for it. Either way, the new model has definitely made its mark.
RIDE A PIECE OF THE PAST
ON THE
PATH LESS TAKEN!
Sometimes we find ourselves in the middle of nowhere.
Sometimes, in the middle of nowhere, we find ourselves.
