XS to Triumph?

Gyllenberg

XS650 Enthusiast
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I heard from a guy that the XS is a "copy" of the Triumph 650 unit engine. He said the motormounts was a nearly perfect match, is that true?

See I got my XS chopper but sorry guys, Triumph is cooler. It just happens to be so that I also have got a Triumph 750 unit 5-speed engine and It would be nice to drive a Triumph next summer ;)

DSC_0236_zps331f7f3a.jpg
 
They( Triumph) may have become " cooler '' but back in their day they were considered big POS's by alot of people. I do like them, however, as I like anything that appeals to me, if it looks cool, sounds good, has functionality, its a win win. But I do believe that these engines designs were scooped up by YAM after they were unsuccessful from other companies years before.
 
They( Triumph) may have become " cooler '' but back in their day they were considered big POS's by alot of people. I do like them, however, as I like anything that appeals to me, if it looks cool, sounds good, has functionality, its a win win. But I do believe that these engines designs were scooped up by YAM after they were unsuccessful from other companies years before.

Anyone who has worked on triumph twins and Yamaha xs or tx twins Should be able to tell there is no similarity between these engines.The triumph is a twin cam push rod design with vertically split crankcases. The Yamaha is a single overhead cam design with horizontily split crankcases. In the era when Yamaha was designing the xs engine their were far superior engines for them to take inspiration from other than the dated triumph design
 
Both are 360 degree parallel twins. What else do they share? Dry sump vs. wet sump. Push rods vs ovhd cam. I fail to see the similarities.
 
The origin of the XS650 engine is German: the early 1950's 500 cc. Horex Imperator, the design for which passed into Yamaha's hands through a series of acquisitions. The story that the XS650 is a knockoff of the Trunch 650 is sheer ignorance propagated by fools who've never owned a Brit machine and know nothing about them.
 
^^^^ This was where I was headed. I was not sure the original name of the group that tried the design first.
 
Maybe it's better looking but it won't be as good. Like Jodi Arias.
 
From what I understand that woman is being housed at an institution called Perryville Prison about 3 miles from my house as she awaits her fate. Now don't that make a guy sleep better at night.
jefft
 
Okay okay, settle down! I havent compared the engines at all whats why I was asking.. And the Yamaha might be more reliable and better, but it will always be less cool than a Triumph ;)
 
Well, "best" is a most subjective matter. One could surely say that working on an older design like the Triumph requires even more skill than working on an XS, so vintage Triumph ownership is surely more demanding, I would say. Looks are purely subjective, so is not really worth discussing. Coolness by racing heritage, is another subjective issue, Gene Romero vs King Kenny....
If accepting the basically reengineered Nourish (Ex Rickman, ex Weslake) 8-valve engine as a "Triumph", then the XS is far behind with regards to potential HP output. A Nourish engine can output above 80 hp........
Another thing with the Triumph, since it has 2 camshafts, 1 intake, 1 exhaust, it is much more "tuneable" without replacing camshafts, as it is possible to alter the valve overlap, just like on DOHC engines..
In European classic road racing, I do believe there are more fast Triumphs than XS 650s...
 
Having actually owned and maintained a 1968 Bonneville (bought new in 1968) and having sold BSA's, I can tell you romantics that there's no high degree of skill involved in keeping a Brit twin running; you just have to do the bonehead maintenance chores more often and accept shorter service intervals (like top end rebuild every 20K miles or so). If that's your idea of cool, go for it.

Gee, a hopped up Yamaha production motor with a 4-valve head can't compete with a Triumph-based race-built 8-valve engine? What a surprise! But I'll say this much for the Trunch; the motor has a serious advantage not only in overall weight, but in where the weight is located.
 
My personal favorite: The crankpin sludge trap...
Forgot about that one!

Anyone else notice the engine is (poorly) photochopped into that bike?

To the OP's original question a buddy put an XS engine into a trump frame he welded in the XS cradle so I will guess the swap isn't all that simple. :wtf:

chase%20chopper.JPG
 
Thanks for everyones opinions and info, greatly apreciated!

Haha not even Photoshop, a quick ms paint fix to get the idea of how the bike would look, didnt do it to fool anyone and honestly thought noone would miss my Paint butchery..

Oh well, guess Ill have to build the Triumph with the frame I got for it....
 
Having actually owned and maintained a 1968 Bonneville (bought new in 1968) and having sold BSA's, I can tell you romantics that there's no high degree of skill involved in keeping a Brit twin running; you just have to do the bonehead maintenance chores more often and accept shorter service intervals (like top end rebuild every 20K miles or so). If that's your idea of cool, go for it.

Gee, a hopped up Yamaha production motor with a 4-valve head can't compete with a Triumph-based race-built 8-valve engine? What a surprise! But I'll say this much for the Trunch; the motor has a serious advantage not only in overall weight, but in where the weight is located.

Sure, the NRE (Nourish Racing Engine) is a purpose built 8-valve engine, with more than a little influence from Cosworth, regarding head design. It is still based on the Triumph architecture, and was designed and developed in the 60s and 70s, the same period when Yamaha developed the OU72 (?)
Don't get me wrong, I still love my XS, its looks and clever design with horizontal split cases and all. I was just trying to contribute to the Yamaha vs Triumph discussion. And Nourish engines are still available, custom made to spec, from 500 to well over 800 cc, 270, 180 or 360 degree crank phasing, several camshafts and porting options etc. However, it is not a unit construction, so requires a separate trans and gearbox. And the most impressive part; it is made by Dave Nourish, now 83-84 years old! So If I had unlimited funds, a Rickman Metisse framed Nourish Triumph would be high on my shopping list :)
 
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