my poor bike

[Brute]

Dude. That is not a rough diagram. A rough diagram is with pen on a paper napkin with coffee stains on it!    Nasty break. Must have been quite scary when it came apart.  

[mxaniac]

Head stay is thick plates welded to a tube the same as the ones that broke.

The beauty of 7005 AL is that it has similair properties to 6061 but you can heat treat it yourself in your oven while cooking a pizza.  It's something like 200F for 6 hours and 320f for 4 hours (Don't use those numbers without verification I'm going by memory).  We had an oven at work large enough for me to do it myself.

thanks for the pics. thats a real interesting break, and looks like youre right in how it broke. looks like the engine got pulled backwards and just seperated itself and the rails from the static Y.
what does your headstay look like? it almost looks like the engine tried to move back 3/4" violently, cant really see how it did that with a solid headstay mount enough for it to straight shear off like the pictures show.
who did your heat treating? not to knock them or say they had anything to do with this, just i only have 1 source so far and they are $$$.

[mxaniac]

I'm not so sure it wasn't torsion at the steering head.  Hard to say but the angled breaks up to the center point make me suspect a beam in bending with half in compression and half in tension.  I'll have to look at the rest of the frame because off the top of my head I don't know how it is braced up and where those types of forces are transmitted.

Because a few people had problems breaking their frame rails I wanted to be sure I understood where the transfer of energy was taking place at.
Here is a rough diagram of where the mounting points are in relation to the frame.

As you can see, when coming down hard on a jump the force is transferred in a radial motion pivoting on the 17mm swing arm pivot pin.
So, the rear mounts must be in line as much as possible with the direction of the force.

[sandblaster]

Dude. That is not a rough diagram. A rough diagram is with pen on a paper napkin with coffee stains on it! 

Ok, well what I meant was that it was measured with a tape measure and square, not a digital protractor and micrometer, or CMM 
Anyway I think it shows why so many are breaking their frame rails as if they were under extreme tension.

[Motorrad]

I know why.

[jBernard]

please do tell. i have anxiety issues so breaking frames is something i'd like to not have to worry about. 

[Motorrad]

https://www.google.com/url?sa=t&source=web&rct=j&ei=WlswU-jxN9jloASn3oCQDg&url=http://www.youtube.com/watch%3Fv%3Dm2G5bldFBPY&cd=2&ved=0CDwQtwIwAQ&usg=AFQjCNF8EIuT3QvaVccs2h86Et1pfTl1vw

[jBernard]

thats scary and now im more anxious.

[Foxx4Beaver]

Steve Harvey was a handsome s.o.b. when he had a carpet on his head.

[mxaniac]

Be nice to have this model:

[mxaniac]

Looks like Service Honda is using an extra gusset across AND a very beefy head stay.

[jBernard]

where do you see a cross gusset on the SH frame?

[mxaniac]

It's right above the motor mount and right below the exhaust in the pictures.

where do you see a cross gusset on the SH frame?

[evergreen]

The first kx aluminium Frame i saw was a Spy Photo of an Kawasaki kx Prototype in 1991. Now i know why they not came out with it before 2006.

[evergreen]

I talked about with my brother he works 20 years in a factory for pipe connectors (Parker-Ermeto). He said there is a Laboratory for Material Control what can exactly say what kind of Material the original Material/Frame is.