[SpudRider]

Originally Posted by 2LZ

Great write-up Spud! Excellent and complete, as always.

I remember back in the 70's, when unleaded fuel first came out, it was eating up the valve seats and the manufacturers had to go to hardened valve seats. I wonder if this is what's happening here?
Did the old valves look worn or just the seats?

Thank you, 2LZ.

Since the valve recession was obvious, I didn't remove any of the valves for inspection. I wanted to ship the untampered cylinder head to Gerry for his inspection. I also didn't care to do the extra work.

Is unleaded fuel required in China? I don't know. If the Chinese are still using leaded fuel, you might very well be correct. I remember reading somewhere that the Italian company, Piaggio, designed the NC250 engine. I suspect the Italians designed the engine for use with unleaded fuel.

I'm hoping my experience with this problem is a rare exception. However, I felt an obligation to warn others who might be experiencing the same problem.