(first posted 4/29/2012. Please note that this article does not pretend to be complete and fully accurate as to the origin and development of the Yamaha 650. A number of comments after the article shed valuable additional light on this bike’s origins and development. ED)
Yamaha introduced their 650 in 1968 as the 1969 XS1. Even though it was widely regarded to be an improved copy of the British 650s, it was not. Across the board, the Japanese motorcycle industry was a hotbed of intrigue. Companies would copy other brands or obtain a license to build bikes developed by others versus doing actual “in house” research and development. Considering the devastation brought about by the second world war, that can be easily understood. The XS1 may have been indirectly a copy but of a bike that most of us never heard of. It certainly had its origins in another Japanese bike. Regardless of its origins, the 650 Yamaha became my favorite street bike. I enjoyed the ride but I also find I enjoy the history. Hope you do as well.
First of all, there was a Japanese copy of a British twin and at least when it started, it was legal. The Kawasaki W650 is the copy of the BSA A500. It was a design that was licensed to Meguro by BSA.
Meguro was the largest motorcycle company in Japan at the time. They came through some hard times and in 1960 they were purchased by Kawasaki. Somewhere along the way the 500 was increased to 650 and the bike became the W650. It was produced until the early seventies, then dropped. It appeared again briefly in 2000. It is still being sold in two sizes in other countries. I believe the Kawasaki below is a later model.
The 650 Yamaha is certainly a copy but not of a British twin. One theory of the genesis of the Yamaha 650 is that it was inspired by a Horex. They were bought out by Daimler Benz in 1960 and ceased production of motorcycles.
If thta’s even true, the Horex design did not go straight from Horex to Yamaha, nor did it go unchanged. A Japanese firm named Hosk appeared to get divine inspiration after an intense study of the Horex bikes. They developed and built a 500cc twin that was essentially the only Japanese bike that that could keep up with the British twins of the day.
Hosk was sold in about the same era as Meguro. It was bought out by a company named Showa which we are told was not the same Showa that makes shock absorbers today. Showa was bought by Yamaha. The same engineers that designed the top of the line 500 transformed it into a 650. After languishing for almost a decade it was released again. This time it was the Yamaha XS1.
Your starving teacher was transferred to Panama in August 1972. As usual there was a sailor who was hurting for money. He had foolishly purchased a 1972 XS2 and now had little money left for adult beverages or female companionship. At the time I had money so I purchased his bike for a sum that was too low to repeat without blushing.
People had liked the British twins for years. They were narrow which allowed for a lot of maneuverability, they were light weight, and they were the natural next step for someone who felt they were ready to move up from the 350 or 450 size.
This bike had a single overhead cam. That made the engine slightly taller than the OHV twins of the day. It also had a shorter stroke and these two factors allowed it to rev forever. The ’69-71 model years had front drum brakes. Period articles indicate that my 1972 was the first XS with disc brakes. It was fitted with a single front disc that did the job very well.
The ’69-71 models were kick-start only. That was something you could live with since it normally started with one or two kicks. The 72 model had an electric start and an automatic compression release. Literature suggests that ’72 and ’73 both had the compression release and in ’74 the starter was upgraded. Memory tells me that was needed.
The pistons rose and fell together. This made for an exhaust sound that was smooth and regular. It also made for a higher level of vibration and the engine came without counterbalancing. 180 degree cranks are available through the aftermarket. The sales pitch is that they increase performance and reduce vibrations.
The crankcase was split horizontally which is something the Brits did not seem to understand. That allowed the engine to be practically leak free. In fact, I lived in an apartment where I was able to roll the bike in my front door. I would have had a hard time keeping a BSA or Triumph in my carpeted living room. In the middle of the model run Yamaha dropped the XS designation. The same bike became the TX650 to provide conformity. They also had 500cc and 750cc four stroke twins with the TX designation but actually different designs. The XS designation resumed when those bikes were dropped.
Kenny Roberts was a road racing legend in his own time. In the seventies it was necessary to compete in both road racing and off road events if you wanted to be competitive. The Harley XR750 owned the flat tracks and still pretty much does. The Roberts team upsized the 650 to 750 and campaigned with it. The picture is of Roberts teammate Don Castro with the factory ride. Finding pictures of Roberts on the 650 is difficult because everyone wants to associate him with the TZ750 in a circle track frame that he rode later. The TZ750 would probably have killed a lesser man. The AMA declared it illegal. The 650 team appears to have existed from 71-75 and kept Roberts in the running for the AMA#1 tag.
This bike was very maneuverable due to its narrow width and responsive engine. Many of the same crowd that made the Honda 350 the best selling bike of its time moved to the Yamaha. Many of them became choppers.
Nobody has ever accused the tuning fork people of being unintelligent. Because of the interest in Choppers they developed the XS650 special.
By the time the line ended (1983 in the United States and 1985 in Canada and the UK) the special was all you could buy. This 1980 Yamaha represents the stereotypical look.
Today the most common format for this bike is the circle track, cafe racer or brat bike rebuilds. However, as you can see, it’s been everything. The bike began as an excellent example of technology. The Hosk 500 was capable of keeping up with anyone. The XS1 had the misfortune of being released in the middle of a flurry of technology that included the BSA/triumph triples, the Honda 750, and the MK1 Kawasaki. It represents milking a design for all it’s worth but it does not represent any real time at the front of the pack. Had it been released when Yamaha obtained it, it certainly could have been a hot rod. However, Yamaha already had one that was less expensive to make and already a legend. As a dependable, agreeable, and easy to ride middleweight it had few peers and at least one fan.
Hope you enjoyed the ride.