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Author Topic: Motor as stressed part of frame?  (Read 286 times)

Offline John R. Mallory

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Motor as stressed part of frame?
« on: March 23, 2017, 09:49:53 AM »
I've heard of older bikes--1910 Indian, Vincent--using motor as pre stressed part of frame. I  don't see it recently. Was it a way to reduce weight or what? Why not still use it? I know Ducati brags of its light weight by monoshock rear ends, etc.
bike looks Sorta like that--I don't.

Offline mollusc

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Re: Motor as stressed part of frame?
« Reply #1 on: March 23, 2017, 10:01:31 AM »
That was one of the main design concepts of the Britten motorcycle of the early 1990s -- extremely successfully. I've also wondered why it's not done more often.
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Offline John R. Mallory

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Re: Motor as stressed part of frame?
« Reply #2 on: March 23, 2017, 10:05:01 AM »
Early '90's? Guess I'm out of the loop.

 I tried Wiki but no clear reference .

They are often fulla S*** anyway, about anything American--I can prove it and I have edited without any repercussions as I had a reference.  I've seen technical articles change radically over the years--a strong "opinion", unreferenced, eventually gets purged.
bike looks Sorta like that--I don't.

Offline mollusc

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Re: Motor as stressed part of frame?
« Reply #3 on: March 23, 2017, 12:23:57 PM »
The Britten V1000 was designed, developed, and built by a guy in New Zealand in his home workshop.  The whole thing is basically carbon fibre.  He even invented the paint because he didn't like the colours that were available off the shelf.  Essentially the only off-the-shelf parts were the cylinder liners, some suspension components, and the brake calipers.
It won a whole lot of trophies before John Britten died in 1995.

https://en.wikipedia.org/wiki/Britten_V1000


NOT American.
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Offline Rakillia

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Re: Motor as stressed part of frame?
« Reply #4 on: March 23, 2017, 02:06:59 PM »
I'm not sure what you mean by "pre stressed" but if you mean the motor is part of the structural integrity of the frame thats fairly common.  SV650 comes to mind because I had one.  Yes, its to save weight.

Offline John R. Mallory

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Re: Motor as stressed part of frame?
« Reply #5 on: March 23, 2017, 02:37:13 PM »
Mollosc, Im sorry I didn't say Britten was American--I said, Wiki is  inadmissible in court (although one tried!), and it  is often  wrong or incomplete,  especially on American subjects: LDS, A/C Cobra,  Chevy Citation (had to edit it myself), Chevy Vega,  Northern/Central California (should see the Talk section--arguments back to '06!), etc.


Rakilla, that's the way it is described to me. If its wrong im sorry.

  I am nebulous on whether  that would be much advantage--seems you only save a few pounds,  even less if Al or Ti or
 carbon fiber--and possibly stress-crack the engine from torque and vibration.

As I said. Wiki gets things wrong. They described the Britten, but did not mention this point. They go on to quote  how Odd it was from NZ--when Burty Monroe hand built his Indian in Invercargill. It has been  surmised  that if he had had  real machine tools, he would have rivaled the Japanese.
bike looks Sorta like that--I don't.

Offline mollusc

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Re: Motor as stressed part of frame?
« Reply #6 on: March 23, 2017, 05:08:16 PM »
I didn't mean to imply that you were saying he was American.  More I was trying to point out that it's not just American topics that get heavily edited on Wikipedia.  Over the past five years or so I have noticed a general trimming of Wikipedia overall; my sense is that if you want gritty details, there will be a website for that, and Wikipedia is just for general overviews.


From talking to John and seeing various documentaries and reading stuff about him, his reason for using the engine was because it simplified things a lot.  You didn't have to design two things where you really only needed one.  Sure it saves some weight -- which is important for a track bike -- but that wasn't the primary idea.
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Offline Wahrsuul

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Re: Motor as stressed part of frame?
« Reply #7 on: March 24, 2017, 04:54:00 AM »
Yeah, Kawasaki used the engine as a stressed frame member in the 80's, the some of the GPz's and later the Ninja had it and still do.  The concours was that way also.  Pretty sure most modern sport bikes still are...

Offline John R. Mallory

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Re: Motor as stressed part of frame?
« Reply #8 on: March 24, 2017, 10:14:26 AM »
Ok.

But Wiki worst on American. Imagine saying  90% of the Mormon brigade voted against  Brigham Young for president...and Vegas didn't have a cylinder wear problem... Northern Ca starts at Ventura....malarkey.

Off Topic.

Guess a few pounds does mean something with racing.

Thanks for the good info chaps. bnna+
bike looks Sorta like that--I don't.

 

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