my poor bike

[DSPMOTO]

its been a couple of weeks since the crash. really dont know why this happen. i have been riding the bike for just over a year  as you can see from my other posts on here. but here is my story on what i remember from the day. i was at a loretta lynn area quailifier  , decided i was going to race my two stroke cause i hadn't rode in a couple weeks and the 450 would have taken the fun out of the day. Got through my first two moto's smooth. Three laps in on my 2nd moto of open prosport me and a buddy were having a good battle. came around to hit the 90ft table just like i would have on any other lap. everything was going perfect until i landed. that is all i remember. my buddy that was less than a sec behind me said that nothing went wrong. he said as soon as my wheels touched the ground i was going over the bars! the last thing that went through my head was, Oh f**k she locked up and I'm going over the bars. turns out the motor didn't lock up but i did indeed go over the bars. i was knocked out cold. guess i ended up laying there for 3 laps until i was able to convince the paramedics that i was ok just got knocked out. after i got back to the truck it took me a good hour to realize what had really happen. when they finally got my bike up off the track and brought it back to me camp thats when i i realized that all my friend were not kidding about my frame breaking in half. i got very very lucky to be able to walk away from the crash with only one scratch! the next couple days after were rough, felt like i had been hit by a truck. so now i have to start all over again. thats the most upsetting thing about it all. i had just finalized everything on the bike. o well , cant wait to build a new one!

[sandblaster]

Holy smokes brother, your one lucky man...
Glad your ok.
Would it be possible to post some close up pics of your head stay area?
It might help save someones life..

[Motorrad]

Looks like it broke at your welds on the downtube?

[jBernard]

ouch. good to hear your OK buddy.

Odd, check out the headstay mount, bracket welded to frame is beefy enough, but the plates used to attach head to bracket look like 3/16" alum. thin stuff. and it ISNT broken doesnt appear. thats surprising.
Like said above looks like broke the rails right below the yoke then just peeled it straight back and broke the main spars.
This is an interesting incident where it looks like the engine forces on landing didnt have much impact on the fracture, but mainly the rigidity of the chassis itself when landing.

[cmotodad]

Did you notice any excess vibration? When we had cracks in our CR500AF, it started vibrating more than normal. Had one crack all the way around the tube just below the weld into the Y.

[motopunk]

bad luck...but nice to sea, that only your bike is broken and you are okay...   

i agree with motorrad.. the welds on the y are broken like cuttings with a saw..   

[LundMx]

Bummer  .

[DSPMOTO]

here are some more pic. I wont upload all of them since you can look at them on my photobucket. feel free to post a photo from there if you would like to discuss it. I should also add that this was my 2nd time riding the bike since I had it down to bare frame to rebuild. when it was apart there was no visual sign of anything wrong with the frame. however I did case a jump the day it broke, thinking that maybe from the shock the frame received from the case is maybe what caused it to break. @cmotodad, no there was no excess vibration,i wish there was so I wouldn't of had to go through the wreck. there was no signs at all that this was going to happen. bike rode like it always did.

[don46]

It looks like the left downtube showed signs of failing prior to the failure, the right side looks like a fresh failure.  This would be another argument for Sandblasters front head stay, had you had one it may have prevented complete failure. Welds appear to have held. I do believe that the factories use the radius tubing to prevent failures like this. Seems like an old welder told me one time that you never weld square, always radius you pieces to prevent failure.

This was a 250 so, all with 500's better look close, really close.

[cmotodad]

I think the headstay had a crack too. Why would the stay have a crack since it is behind the break? Just a thought.

[sandblaster]

Just curious, did you stress relief the frame after weld and then heat treat?
I wondering how many actually do?
Does Service Honda?

[motopunk]

after the new closer pics of the y, i have to say that the weldings still look good, but the quality of the frame-rails-aluminium seems to be to low. very thinn walls also..  
 are the frame rails selfmade? or which one do you bought?

i love the look of the al-bikes, but there is so much to watch out in cutting and welding on it what it makes a little bit dificulter than a steel-frame-conversion. in theory aluminium needs 3x thicker walls than steel, to get the same durability which make an al-frame not as half as flexibel compared to a steelframe.

just found this frame  , hope it helps to bring your bike back to live...  

http://www.ebay.de/itm/Kawasaki-kxf-250-kx-250-f-main-frame-A1004-/251273932896?pt=UK_Motorcycle_Parts_13&hash=item3a8117f060

[Motorrad]

It looks like the left downtube showed signs of failing prior to the failure, the right side looks like a fresh failure.  This would be another argument for Sandblasters front head stay, had you had one it may have prevented complete failure. Welds appear to have held. I do believe that the factories use the radius tubing to prevent failures like this. Seems like an old welder told me one time that you never weld square, always radius you pieces to prevent failure.

This was a 250 so, all with 500's better look close, really close.

I 100% agree with dons observations here.


Never weld square tube.. in applications like this.    the corners are stress risers...

[jBernard]

i know the hondas use some specialty extrusions. looks like square for half of it, then a chamfered edge on the outer side.


how are you supposed to radius square tubing though? just bevel the edges? to put any kind of radius on it youre taking a lot of material off and leaving the corners thin. seems like it would help the stress point, but in turn be an issue in itself.

[cmotodad]

There is a radius 1in sq tube avaliable. The guys on banned buy it all the time. Same wall thickness as stock CRF and radius inside and out.