How bad does my bottom end look?

Ladies and gentlemen, I could use some advice.

I have an 01 YZ125 that was converted to a 144 by Eric Gorr.

I was letting a friend ride it a few weeks back when the motor seized.  I think it may have been running too lean, but what's done is done.

It looks like the piston pin or bearing failed which led to the connecting rod's reign of terror inside the motor.  

Check out the pics, there's some gouges inside the top of the bottom end.  Would it be ok to Dremel/polish the gouges down, rebuild and run it... or should I send the bottom end to have material added and smoothed?  The top end will be sent to Eric Gorr for sure.

Hi Res pics here:

Thanks in advance!



Edited by CrimsonSky

You’ll be digging deep into your pockets to do the job properly. My advice two brand-new cases


Your engine needs a complete rebuild

It can be patched up - have to strip it down completely of course

I would strip that down and split the cases. As long as no mating surfaces are gouged and nothing is cracked, I would take a dremel or a file to it and take off any material sticking up, as well as knocking down any edges and removing any loose material. 

As long as no mating surfaces are damaged or anything is cracked, you’ll be okay. 

Those cases were machines for the 144 kit right?

Open it up, I would say you are good to go with cleaning up all the hi spots. No need to fill lows. But what it did on the thin walls of case in crank housing may be a different story. 

Good luck, let us see the split cases. 

Id look at it as now when its split you can match up to cylinder while in half. Clean an polish 🏁🏁

I'm going to split the cases and take it to a shop in the bay area.  I'll make sure to update the thread with pics of the inside of the motor.

Looks like it failed at max rpm. It would have sounded like shit before it happened.

Cases don't appear to be matched to the 144 piston. Did you only have the top end done?

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