Metro connecting rod damage

[tucker]

I know it's not a Spree/Elite question but this is where the expertise resides. I have completely disassembled a Metro engine and found the rod connection at the crank is moving about .030 up and down. Side to side clearance is fine. Top connecting pin is in very good condition. Looks very normal. Very little piston scuffing, almost looks very normal. Engine otherwise is in excellent condition. I am baffled as to what caused the damage. It is a 12.0-1 compression engine, would running it on 87 octane cause enough detonation to do that without any obvious damage to the piston top? All the internal bearings and surfaces look good. I don't have a reliable maintenance history from the previous owner, a 300 lb rider in extremely steep hills. The clutch outer housing was blued pretty badly from the heat and the brakes had been working equally hard. Less than 4000 miles on the scooter. Any insights or opinions would be appreciated.

[Kenny_McCormic]

Does it use a pressure lubed system or is it all splash lubed? I can see a clog in the crank doing that.

[tucker]

Does it use a pressure lubed system or is it all splash lubed? I can see a clog in the crank doing that.

Pressure.

[Wheelman-111]

Greetings:

I will bet it's a 2005 or earlier. Few people know less about Mets than me. I have read however that Honda committed a rare engineering error with its earlier Met models. The crankcase ventilation system was inadequate and allowed too much blow-by contamination of the oil. The Lube system failed often before 4000 miles resulting in this kind of damage.

Honda revised the system in ,06. There may be a recall remedy even for used bikes.

[scooterwerx]

exactly, if its a 05 or older, they suffered from bottom end lubrication woes...

[tucker]

Greetings:

I will bet it's a 2005 or earlier. Few people know less about Mets than me. I have read however that Honda committed a rare engineering error with its earlier Met models. The crankcase ventilation system was inadequate and allowed too much blow-by contamination of the oil. The Lube system failed often before 4000 miles resulting in this kind of damage.

Honda revised the system in ,06. There may be a recall remedy even for used bikes.

Your are correct. It is a 2005 Met II with about 4000 miles. It has a reed valve type of crankcase ventilation system that lets the gases go back into the air intake. What type of failure did the lube system suffer? Was it the pump or just the contamination of the blowby gases diluting the oil? Would love to know so I can maybe remedy the situation on the rebuild. Will check into the recall aspect. Thanks a bunch.

exactly, if its a 05 or older, they suffered from bottom end lubrication woes...

That is what I am seeing on the crank connecting pin of the rod. Thanks for the info.
Like I said in my post, this is where the expertise resides. If anyone has a Honda TSB or any other reference I would appreciate it.