ATACC on 02 MM700

[firefighter]

I have had an ATACC on both of my 02 MM700 and one on my son's 00 MM600n for 4 yrs now. So far I have been really happy with them. The question that I have for all of you home mechanics out there is this. Has anyone experienced the ATACC running lean conditions enough that would cause the pistons to score.

My wifes machine developed a knock in the #3 cylinder (mag side). In my attemps to find out what it is I have pulled the flywheel off to see if the key was still there and not spinning and it checked out ok. Next came off the cylinders. #2 & 3 both have bad scoring. Enough to put gouges in the cylinder walls. #1 was just fine. I run Amsoil in the oil tank. All the pistons seemed to be the same tightness before the jugs were pulled and it had lots of compression. No problems running, I just didn't want something to let go while riding it. Any coments or suggestions is greatly appreciated. Oh, one more thing, Stock pistons or Aftermarket. Thank you for the help

 

[Ford428CJ]

Bad scoring on the exhaust side of the piston? You need to really look @ your plugs and piston wash!!! And keep an eye on that stuff. So when you put new piston/rings in, that wont happen to you again. Pictures would help.
Sounds like you need to dial up your ATACC..... JMHO

 

[treemagnet03]

I have had an ATACC on a MM700 for 4-5years now without concern. However, the baseline was set in minnesota, so a lot fatter to start with. That could be part of the problem for you-too lean to start with? What was the temp outside when you set it up? I second that you really need to watch the pistons/plugs if you are concerned...

Good luck

-T