some xs history,part #1

drog

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From being on a few different xs650 sites i have noticed quite a bit of misinformation and confusion concerning the origin and history of this cool little bike.I make no claim that i have all the answers by any means,but having worked for a major parts supplier for these machines and through some research i have learned some interesting facts about them. To understand the why,when and how the xs came about, you must research some of the history of Japan's early vertical twins,with names such as Cabton,Meguro,Showa and of course,Hosk.I am not going to give a full history lesson here,as i do not possess the full knowledge to do so,or the time,but i will throw a little interesting info out there for you that may spur your desire to do some research on your own. From what i have gathered,Cabton got started in the late 1930's building bikes,and built it's first OHV Twin in 1950,a 500 c.c. 24 H.P. model.In 1955 Hosk introduced its own 500c.c. model,The Road King! Yes,The Road King.Name sound familiar?It had a 63mm bore and 80 mm stroke,498c.c.The final model,in 1960,was good for 110 mph with it's 40 horse engine.There has been discussion that the xs650 introduced at the Tokyo Motor Show in 1968 is really the Hosk!If that is true,then our beloved xs 650 has the right to claim to be the next -to- first vertical twin from Japan!
 
From what I have read the Hosk was a german bike. When Hosk went under Yamaha bought the bike and with a few changes built the 650
 
I only know what I've read on Wikipedia about the subject. It cites almost all of its sources from biker.net. If he's got it wrong, then through Wikipedia, there is potential that hundreds of thousands of people have been mislead regarding the history of the XS650 . :shrug: Not sayings it's wrong, but what if it is? So I'm curious to hear what people have to say that differs from the biker.net resources.
 
Not sure where the story of it being developed with Toyota fits in, I saw a write up once of the car it was supposedly developed with and even this mentioned the xs.
Inxs has told me where it fit's in in the past, but the memory isn't what it was.
 
Xsleo,Hosk was a Japanese company,perhaps you are thinking of Horex which was German.It seems that Hosk copied the Horex design,then when Showa bought them out they later developed a 650cc version of the 500cc Horex.Yamaha later bought out Showa and went on to produce the xs650.Kinda confusing,but interesting.If you can locate a November 1983 issue of Rider magazine,it has a great little article on the early Japanese twins by C.D. Bohon.I have not heard of any Toyota involvement before,would like to here actual facts about that one.Thanks.
 
just found it:

yamaha used the knowledge gained with the acquisition of showa and their 4 stroke technology to work together with nissan on their nissan 2000gt-when nissan withdrew from the project yamaha approached toyota who ran with the ball...they used the same bore dimension and a 1mm shorter stroke in the XS, used the same pistons cast however in Lo-Ex to compensate for air cooling, the same valve geometry albeit with only 1 ohc and the same valve keepers...interestingly a german designer-albrect von goertz was customising ford model a's and b's stateside in the late 30's, after spending 5 years in the american army he was spotted by raymond loewy who trained him and set him to work with studebaker, from there he went to bmw and later to nissan, working on the 2000gt project he transferred to toyota...something must have gone wrong as his last design was a steinway grand piano for their 125th birthday celebration in hamburg...ka kite...enjoy...
 
Hi All:

I realize that this is an old thread and in fact, most of the contributors to it may not even still be active on the XS650.com forum (but at least one is....gggG ;)). Anyhow, with the XS650 being the featured marque at the upcoming CVMG Paris Rally, I was asked to write a little article on my bikes for our local chapter. I did that and apparently, it is going to be picked up by the national newsletter as a feature.

Anyhow - in the process of doing that work, one of my riding buddies ran across another piece of XS650 history: a Hosk DB 500 trading card from 1958 that had recently appeared on eBay - and here it is:

HOSK - DB500 s-l640.jpg


Pretty cool eh?

Pete
 
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Separate crankcase and transmission on the Hosk - a big jump had to be made to the XS unit construction.
Wish I could remember the source of the article I was reading last week that showed a stronger 2000GT connection.
 
Indeed. Certainly, Yamaha has done high performance engine work for various OEMs over the years.

A good example was the mid 90s Ford Taurus SHO - unless I am mistaken, that big V6 engine in that machine had been built by Yamaha.

Pete
 
Indeed. Certainly, Yamaha has done high performance engine work for various OEMs over the years.

A good example was the mid 90s Ford Taurus SHO - unless I am mistaken, that big V6 engine in that machine had been built by Yamaha.

Pete
I thought it was designed by Yamaha and built by Mercury Marine. This from memory, so.....
 
Yamaha is owned by Toyota
That might be a little strong.....

March 13, 2000 12:00 AM
Toyota buys 5% stake in Yamaha Motor Co.

TOKYO - Toyota Motor Corp. is pulling Yamaha Motor Co., maker of motorcycles and performance automobile engines, into its fold.

Toyota will buy a 5 percent stake in Yamaha Motor from Yamaha Corp., which owns 33.3 percent of Yamaha Motor. Toyota thus will become Yamaha Motor's second-largest shareholder, at a cost of about ¥10.5 billion, or about $100 million at current exchange rates.

This investment and a similar investment in Toyota shares by the two Yamaha concerns aim to strengthen the companies' cooperation in three areas: the development and manufacture of vehicle engines, motorsports and marine engines.

Toyota President Fujio Cho called it 'a major milestone for us.'

Yamaha Motor and Toyota have a relationship that dates back 30 years, when Yamaha first supplied the engine for Toyota's 2000GT sports car.

Yamaha Motor currently supplies engines for Toyota's RAV4, Supra and Altezza, known in the United States as the Lexus IS300 and in Europe as the IS200.

Yamaha also has supplied engines to Ford Motor Co., most notably for the late Taurus SHO.

Despite the tie-up with Toyota, 'We will retain our independence,' said Yamaha Motor President Takehiko Hasegawa, who worked on the original 200GT project. 'Our relationship with Ford will remain unchanged.'
 
Hosk bought out Horex designs and tooling when Horex went broke, Showa bought out Hosk, and Yamaha bought out Showa, acquiring the basic design for the XS650 in the process. It's worth noting that Hosk made more than one verticle twin motorcycle. If you do a little search work you'll find that the Horex Imperator, made in both 400 and 500 cc. displacements, used unit construction and wet clutch. Ever wonder why only one Yamaha motorcycle damped the drive train with a sprung primary gear instead of a cush hub?
 
I keep wondering how all that deep 4-stroke design experience on the GT2000 informed the engineering team that put needle bearings in the small end of the connecting rods of the first run of XS1 motors, decided against a counterbalanced crank, and came out with a motor that does not resemble any other Yamaha 4-stroke motor in any significant way. The story connecting the GT2000 project to the XS650 was a clever piece of marketing that stopped just short of a baldfaced lie. Old stuff wasn't in fashion then, so Yamaha couldn't have gotten any sales traction out of basing the motor on a 1954 German design.
 
that stopped just short of a baldfaced lie.
I'd say it crossed the line into a tall one. ;)
The GT2000 engine was basically a standard Toyota cast iron water cooled six that Yamaha added their own designed DOHC head to. Cast iron and DOHC are not attributes normally thought of when looking at the XS650.

gt2000.jpg
 
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