Auto-tuned piston

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Customer is always right. Install the $300.00 carb kit and be done with it. Oh, and stop breaking his piston, that saw ran fine other than the carb kit thingy.
 
Interesting burn mark and crack off to the left over the pin. What happened?
 
High hours and slapping is my guess. Looks like he got his moneys worth outta that carb kit.
 
At this point I don't know what happened. The saw is 100% stock, and doesn't appear to have a lot of hours on it (saw is in good condition and there is still visible crosshatch in the cylinder bore). It was in commercial use for one year, but according to the owner wasn't used heavily because none of the crew liked running it.

While this saw was torn down, another customer came in the the shop, also a logger, and had some choice words for his 576AT that also "blew up", but in less than 6 months. He took it to the dealership where it was purchased from, he didn't know the details other than that they told him the engine was blown and it wasn't worth repairing. I don't believe I know a single person around here that has had a good experience with the 575 and 576.
 
Other than those little crack thingys that piston looks fine! Color looks good, etc. That mark on the top and the marks on the skirt in the port opening are strange.
 
I can see poc marks from detonation on the land above the top groove. Crap gas is likely the cause, and the non-AT saws may have been tuned rich enough to pass. Looks to me that once again the problem lies behind the handle.
 
If it doesn't get used as much as the other saws I'd say crap gas.
 
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