Frame Fatigue

[jamesallan]

I'm no engineer, but a crack like that suggests a major head-on, doesn't it?

Cheers pan,

No pranges according to the history but very untidy to find.

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Just at a guess I would say that the when motor has been put in frame at some stage the right hand side mounts have been tightened up first and then the left one's (several right mounts are adjustable)............. this will place stress on that mount point and the stress created will cause it to fatigue and fracture over time. Motor must be tightened from non adjustable side first then adjustable mounts tightened to motor then clamp bolts after that. Either way I would say stress fracture has been caused by motor which is a stressed part of the frame being mounted incorrectly rather than caused by collison damage.
Also agree with Bruce .............. certianly not by excess power.

Thanks Fasterfaster,

That would make sense based on all the history and deatils that i have picked up since getting the bike. That is a better outcome than plain old fatigue that might crop up in other spots so i will go ahead and get it repaired. Suppose I should consider re checking the engine mount torques and sequence of of adjustment - perhaps get this done after the crack gets welded. happy for any advice.

Cheers James

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In relation to Fasterfaster's possible explanation, have a look on a zx14 site for threads related to the 06 and 07 model recall (frames breaking due to overtightening of engine mounts).

Thanks Gazzabusa,

I had started to filter through some of the older posts. Will check out the ones you listed, much appreciated.

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Pete's explanations sounds plausable, these frames have handled several hundred horses without problem.

Good luck with it.

Cheers,

i don't feel quite so sick as before, yep sounds like this is the reason.

cheers