91 Yam 225: Will this engine run?

mcm114

Cadet
Joined
Jul 4, 2007
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18
See the attached photos. You can see how the con-rod on this cylinder has carved a nice little groove into the counterbalance, and the amount of material that has been shaved off the con-rod as well. I can't imagine how that could happen, unless the rod bearing was so sloppy that it allowed the rod to just rest against the counterbalance, and gravity was enough force to gouge it like that. A sucked reed could be to blame, indicated by the dents in the cylinder head. All the other heads are smooth. You can also see how the piston has stamped the word "up" (backwards) into the head because of the excessive free-play. This engine is 16 years old, has 1200 hours, and has been bored out once already. I intend to replace the cylinder head and the rod/piston assembly, and probably bore the cylinder. Is there any reason why that wouldn't get it running again?
 

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