2004 WR450 rebuild carnage inside

I'm helping a friend out with an engine rebuild and I figured I would share here- bike "locked up" on him when out in the So Cal desert riding. I had no idea what I might find, but I think this might be the culprit. 



It appears as though whomever did the last top end neglected to install one wrist pin circlip. 20 hours on this engine since rebuild. wrist pin walked out the left side, made contact with the cylinder wall, and then got cracking on destroying more stuff. 



Thankfully the exhaust side of the cylinder skirt was there to take the hit from the wildly flailing rod, instead of knocking an inspection window in the front of the case. 



Maybe some JB weld and a buffing wheel will fix this. 



This is the future of four stroke technology. variable axis connecting rod. or not. 




So kids- double check your work and make sure the retaining clips are in the groove correctly. Owner is now on the hook for another $800+ in parts just to get it back to normal. 



That's pretty ugly, +1 on double checking everything during assembly and taking your time.

Serious Carnage.


Sorry for that.


I have a 'friend' who can visit the previous mechanic, if you need one.

Bike locked up out near Soggy dry lake on a 40 mile ride. split the cases tonight, and the good news is most of the debris is large- not much bearing contamination. found circlip #2 in the bottom of the case, so my guess is that the installer didn't get the clip in the groove. 5 second mistake caused almost $800 in damage in parts alone. My labor is free, so he's saving a bit there. Just fedex freight from Ca to CO and back and some consumables here.

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