Break In Break in Secrets



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Guest

Guest
YES! That's the good one.

Take your time and read it all, lots of good info there.
 
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Hugemoth

Guest
Many years ago Vespa did a scientific study to determine the best way to break in their 2 cycle engines. The study was conducted on their 50cc moped engines which are rotary valve, cast iron cylinder, bronze wrist pin bushing. Some were driven slow and easy, some were driven at a steady moderate speed, some were driven wide open. The conclusion was that it didn't make any difference.

The Chinese engines are somewhat different in that they use a chrome bore and soft rings.

Moth
 
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Guest

Guest
The Chinese engines are somewhat different in that they use a chrome bore and soft rings. Moth[/quote said:
All the more reason to break it in like you stole it. It hardens the soft rings and seats them in the bore.
 
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Hugemoth

Guest
The only thing that would concern me about running the hell out of a new engine would be the wrist pin bushing. I've seen a couple of them spin in the rod, causing the oil hole to get out of line with the oil hole in the top of the rod. That may not be a big deal.

Moth
 
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Guest

Guest
Yes, but wouldn't you agree that if the bushing was going to move, it's going to move regardless of how much time or stress is put on the engine?
 
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Hugemoth

Guest
I think the bushing is more likely to move when it is new and tight on the wrist pin.

Moth
 
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Guest

Guest
Also, this notion of breaking in an engine "like you stole it" or "like you are racing it" is a bit of a misconception.

The idea is not to beat on the engine, but to run it at various on/off throttle loads, with plenty of wide open throttle (which is different from high RPM running, which is different still from running hard up against the redline.)

The use of this type of break in allows the rings to seat and to use the engine as it was designed, not beyond it's limits.
 
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