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General Category => Maintenance => Topic started by: Senator_Kang on September 02, 2014, 03:16:07 AM

Title: Dirty oily pistons
Post by: Senator_Kang on September 02, 2014, 03:16:07 AM
Hello!

I took my carbs off for a clean and thought I'd change the spark plugs while I had the tank off. I took a quick peek in at the pistons, and they're gunky and look quite oily! I understand some carbon buildup is supposed to be normal, but is the oilyness 'normal'? I mean, it does consume oil, and I'm pretty sure that the valve seals are gone as it only blows smoke on startup and once warm it appears fine (smoke-wise that is).

I suppose the question could be better worded as "is it a normal symptom of worn/dead valve seals to have oily dirty pistons, or does it point to something worse?"

Thanks!
Title: Re: Dirty oily pistons
Post by: Senator_Kang on September 02, 2014, 03:19:44 AM
I also did a quick search on the forum and the closest I could come up with is this: http://www.fjowners.com/index.php?topic=9369.msg88786#msg88786 (http://www.fjowners.com/index.php?topic=9369.msg88786#msg88786)

Where Firehawk goes into saying there could be an oily buildup on the spark plug itself. Which, well they were black (except for number 4, it was white and I assume running lean). There was some oil on the threads, but that's coming from the stuffed valve cover gasket.