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"Crash forces ripe through the bike finding the weakest point to have an effect. Frame breaks at weld."



Except a weld should not be the weakest point. A weld like a glue joint should be stronger than the surrounding material.

 

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I'am not an engineer or a metals expert however the break looks like a typical surface weld break on very thin metal, even a wood glue joint on thin wood will break at the joint almost every time when subjected to stress beyond it's design .I think it will be hard to prove a defective weld when you crash at 100mph .My advice is to buy a Ducati and then the the frame will be destroyed by bending rather than breaking.
 

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Re: Inquiring Minds Really Blow!

Oh great, MoMONs! Next there will be Monday home race meetings, Then garage priesthood, then.........polygamus motorcycle ownership Whoooo Hooo!
 

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Re: Inquiring Minds Really Blow!

LOL don't forget missionary work on mopeds, white half helmets white shirts and black neck ties of course. Then there is the Book of MoMON by the Great Motorcycle Prophet :) Dare I say more (no better not my wife has me on a short leash probation SA, my remarks must be sincere and respectful the new meds and diet help too.) My praise for SBP, SA, GABE,Fonzie, Ashley, BMW4VW, Buz,Steven etc during my undercover time was real and sincere. MO is great and life is good when you ride and when people give you second, third ... chances...
 

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The fact remains that frames are not supposed to come apart after a crash much less before one. Have we all forgotten the Triumph recall of Daytonas where the factory replaced the whole frame at no cost to the owner because, in certain crash situations, the steering head had a tendency to separate from the frame in head on collisions? No doubt a costly acknowledgement by Triumph that motorcycle frames are suppose to hold together, even in a crash.



 

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One more thought. No question the weld connects an extruded member to a cast member. Going from top to bottom look at the last two photos. The last photo is clearly the extruded member, with the supporting rib running the length of the extrusion. The photo before the last is clearly the cast member with a "bulkhead" running across the casting, also the grainy surface is clearly visible in the casting.
 

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exactly. That weld hasn't penetrated even 1/4th of the way. It's scary to think that you'd have to worry about the welds on a frame. The welds, if done properly, should be the strongest piece. Evidently, this particular weld, was not.
 

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Aluminum versus steel

I can't speak to absolute strength of frames, but aluminum is a brittle metal, meaning that it is more likely to crack from vibration than a more ductile metal, like steel. Aluminum frames are stiff, with less flex than steel frames.

True, you get more strength per pound from aluminum, but that strength is possibly a trade off for longevity when compared to steel. After all, no matter how well damped, there will be vibration on a motorcycle. This question seems to be one that no one wants to address as they chase the all important factors of light weight and low cost. Steel trellis frames are expensive to manufacture, but very light weight compared to other methods of building a frame out of steel. (Check out the dry weight, and price, of a Ducati 1000DS.)

All I can say is that I have never seen a frame failure on a Ducati, other than those caused by impact with large, stationary objects. Even twenty year old Ducs have good frames. I do know that Ducati "tunes" the flex for their frames. Some mechanics also claim that male slider forks are too stiff for use with frames that have no flex, as is inherent in an aluminum frame.

As for controlled fill, Suzuki has the technology. Their literature claims that they use it on the SV frame. So it would surprise me to find that it is not on the GSXR series.

Maybe I'm wrong about all this, but flame away.

Francis
 

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I kind of agree here. How often do we see a bike's main frame spars crack in two, even in the most brutal, end-over-end catastrophic crash? Sometimes the forks are bent so far backwards that they indent themselves in the radiator, or even snap right off, but the frames aren't supposed to break.
 

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LEARN TO WHEELIE RIGHT AND THEY'LL BE NO PROBLEMS, OK I feel better now!!! Jezz?
 

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Which is why Motorcycle.com is the only site work lets me get on. So yes sometimes Iam bored. But the thing that burns me up is stupid, post. And this one takes the cake!
 

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Yeah Moto57 no problem there, except the rider apparently didnt know how to ride, that's the only problem I see with all those pics.
 

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Yeah Moto57 no problem there, except the rider apparently didnt know how to ride, that's the only problem I see with all those pics.
Then, why aren't there a lot of busted up Kawasakis, Hondas and Yamahas? That would seem to me to indicate a design or manufacturing flaw. Certainly a race replica should be able to withstand a few wheelies. I'm sure you have more experience that this sort of thing in a dealership. Do you see other bikes coming in with busted frames at your shop?
 
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