Bottom End Gone!

[julian5000]

Hi All

Just looking for thoughts and advice on my 2011 EC250. Pretty sure something down low has spat the dummy!

I was riding couple weekends ago, first it died (almost as if it had lost all spark), but it kick started easily and was off again. Was running great then oops! Rear locked up and I came to a grinding halt.

The kickstarter was jammed so I put it in neutral and luckily there was towing available, so I rode the ATV Of Shame back to the trailer.

The kick starter didn't take much to move, pushed it by hand and it didn't take too much to get it moving again. But it wasn't feeling or sounding too happy through the stroke.

I stripped it down and this is what I found, nothing major wrong I could spot up top:











Here's a video of the piston:

https://imgur.com/a/EcljJIZ

I did find the bolt that holds the power valve lever arm at the top was sheared off, but it was in place and enough was left to stay in place, this pic from RockefellerGG's excellent rebuild thread:



Down below things were a bit more interesting. I couldn't feel any up/down movement in the conrod, and the big end bearing feels smooth as, and what I can see of the roller bearings look good.

But something down here's not happy! These flakes were plucked from a nook in the crank:



There seems to be staining on the crank but no pitting that I can feel:





I'm still not sure if I will split the cases myself. I haven't done it before, but there's some great resources such as the thread I mentioned.

Any tips or tricks or things to look out for? Any alarm bells or warnings for me to heed? There's a few parts lists floating around, I'm pretty keen to do it all properly and make the motor like new again. I've done pretty much everything else on the bike, and it's such a good bike for a shorty like me.

Cheers in advance for any input. If there's interest I'll post my journey!