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Was the XS650 Yamaha's first production 4 stroke?
- Thread starter redbug2
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TeeCat
One-Mik Wonder
Yes, I believe it was. Somewhere on here, there's a bit of XS650 engine "genealogy" that references that, as I recall.
TC
TC
1974jh5
Curmudgeon.
I believe it was. Funny thing about Yamaha and 4 strokes: back in 1998, Yamaha led the 4 stroke off road revolution with the YZF 400. I still remember Doug Henry winning at Las Vegas with the original 'works' bike. It sounded so weird, the big booming 4 stroke running with the ringdings- and just running away. Being a longtime thumper guy, I rather liked that. 
littlebill31
Smells of Raw Fuel
I raced motocross when I was a kid and still remember having to keep my 60/80 wide open to make certain sets of doubles or to get up on a camelback. Sounded like killer bees. But the 500 2-strokes, back when they were still raced, had just a "hubba-hurp...rup-rerp". Almost seemed effortless. I still love the sound of a 2-strokes.
So much so that several engine design features were later found to be not so good for four strokes. I believe roller small end bearings was one such Oopsie.
CDNTX650
XS650 Guru
yup, 256 motors had roller bearings on the small ends....they dont like 4 stroke power pulses to much...
adk_rider
XS650 Enthusiast
I also remember seeing Doug Henry race to at the Broome Tioga National in NY on the big four stroke. Love the sound of a two stroke but it was cool to hear the pounding of the thumper over all the 250s.
Only the early XS1 motors had this. I guess it didn't take them long to figure it out it was a bad idea. I have an XS1B, also a 256 motor, but it has normal bushing style wrist pins. Some online parts fiche incorrectly shows my bike as having that bearing but I have the original yamaha XS1B manual and it explains what I said above, only "early xs1 utilized a needle-type wrist pin bearing."
Right you are, GreasyC. IIRC the shift to plain bearing wristpins was a midyear change in the XS1.
And right, the XS1 was Yamaha's first production 4-stroke. The motor is essentially a punched-out version of the early 1950's Horex SOHC 500 cc. twin, which Yamaha acquired after Horex was sold lock, stock, and barrel to a Japanese firm, changed hands a couple of times, and found a home with Mamayama. This origin is the reason the XS650 mill resembles none of Yamaha's other engines, which were designed in-house. Fairy tales about the motor being jointly developed with Toyota's racing program are basically face-saving propaganda. The XS650 was a stop-gap item that met with unexpected success.
And right, the XS1 was Yamaha's first production 4-stroke. The motor is essentially a punched-out version of the early 1950's Horex SOHC 500 cc. twin, which Yamaha acquired after Horex was sold lock, stock, and barrel to a Japanese firm, changed hands a couple of times, and found a home with Mamayama. This origin is the reason the XS650 mill resembles none of Yamaha's other engines, which were designed in-house. Fairy tales about the motor being jointly developed with Toyota's racing program are basically face-saving propaganda. The XS650 was a stop-gap item that met with unexpected success.
yamasarus
XS650 Addict
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The first 3269 XS1s had the needle bearing top end. When it let go, it would do it with enough force to put the rod through the bottom of the case. In 1970 dollars that would total the bike. Remember that back then the machines only had a 3 month 3000 mile warranty.
Yamaha was very involved with the Toyota 2000GT in the 60s. For more info here is a link
http://www.japanesenostalgiccar.com/article.cgi?section=profiles&article=toyota2000gt
Yamaha was very involved with the Toyota 2000GT in the 60s. For more info here is a link
http://www.japanesenostalgiccar.com/article.cgi?section=profiles&article=toyota2000gt
Great link on the 2000GT, Thanks.
1974jh5
Curmudgeon.
The 2000GT was a fantastic car. Trivia: the American Peter Brock was supposed to race the 2000GT and at the last minute was ditched by Toyota in favor of Carroll Shelby, who was at the time Brock's boss. Brock then formed BRE and started racing Hinos, that company was later bought by Toyota then went to Datsun where his team's efforts culminated in the 510's which came out of nowhere to win the small bore Trans Am championship.
Shelby's 2000GT C Production effort failed due to modification restrictions, it seemed the Toyota powerplant was capable of much more HP than it made stock but the Weber carbs etc needed were not legal for the class. So Brock got the last laugh on his old boss.
Yamaha also designed the Taurus SHO engine and IIRC had a hand in the development of the Corvette ZR1 engine, although most of that was done by Lotus. They also collaborated with Mercruiser on several engine designs. Mercruiser also built the first ZR1 engines.
Shelby's 2000GT C Production effort failed due to modification restrictions, it seemed the Toyota powerplant was capable of much more HP than it made stock but the Weber carbs etc needed were not legal for the class. So Brock got the last laugh on his old boss.
Yamaha also designed the Taurus SHO engine and IIRC had a hand in the development of the Corvette ZR1 engine, although most of that was done by Lotus. They also collaborated with Mercruiser on several engine designs. Mercruiser also built the first ZR1 engines.
1974jh5
Curmudgeon.
True, and the next thing you know Yamaha developed a lightweight 'lectric leg. DH is a tough sonfabitch; he broke both wrists at Red Bud, came back from that, then left bikes and went to Snowcross. He kept riding outdoor MX and crashed hard at Southwick in 2007, breaking his back again. This left him a paraplegic.
DH in 2009:
DH in 2009:
Pawl
Pawl
check out this thread. The links don't seem to work tho?
http://www.southbayriders.com/forums/showthread.php?t=22391&page=2
http://www.southbayriders.com/forums/showthread.php?t=22391&page=2
1974jh5
Curmudgeon.
I thought 'Horex' was the German company and 'Hosk' was the Japanese company that plagarized Horex's design? Hosk was bought by Showa which was then bought by Yamaha.
Horex: http://en.wikipedia.org/wiki/Horex Says in the Wiki that Daimler Benz took over Horex in 1960 and killed the motorcycle production.
About Showa: for years it was a source of giggles in the dirt bike world that Hondas used suspension parts made by Yamaha. Kayaba (KYB) was a big supplier for Honda as well. Harley buys its suspension stuff from Showa as well.
Horex: http://en.wikipedia.org/wiki/Horex Says in the Wiki that Daimler Benz took over Horex in 1960 and killed the motorcycle production.
About Showa: for years it was a source of giggles in the dirt bike world that Hondas used suspension parts made by Yamaha. Kayaba (KYB) was a big supplier for Honda as well. Harley buys its suspension stuff from Showa as well.
No plagiarism was involved; Horex (German company) was sold to the Japanese lock, stock and barrel. I suspect that "Hosk" was as close to "Horex" as Japanese phonology could get.
Love it!!! goes great with the morning coffee......Always good to start the day with a good laugh.
I saw a cartoon where two rough guys are standing beside their motorcycles and a meek-looking guy is talking to them, with the caption "Mine's a piano."
