Is my piston or cylinder cooked
- Thread starter Skullcmd
- Start date
Johnny_
Well-Known Member
So you're saying it hasn't fired even? Did something get in there to cause the scoring? And what engine is that? (Please pardon all the questions lol.)
Most likely some metal dust got inside, it's a yd100
Johnny_
Well-Known Member
I'm not sure, I'm sure someone with experience with that particular engine will chime in. It's really hard to tell from the picture but it looks like the rings may not even reach where it's scored. The ports do look really sharp so perhaps the rings are snagging. Before starting engines for the first time I oil the cylinder, that helps prevent this from happening.
And worst comes to worst....
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Gordy
Well-Known Member
Does your finger nail catch it?
Chainlube
Well-Known Member
That mark is most likely made from a piece of casting flash that broke off and went between the piston and cylinder wall.
robe
Well-Known Member
Most folks go over the port opening on new cylinders with at lease some 150 sand paper to clean up the rough castings that snag the rings.
May not be too late to clean up those ports. Just need some paper wrapped around your finger and try and sand those edges down.
May not be too late to clean up those ports. Just need some paper wrapped around your finger and try and sand those edges down.
The port edges look rough in the pics- probably metal fragments from there
Scratch/gouge is towards the bottom of the cyl, you still should get good compression
lightly sand the piston skirt, Hone the cyl, clean up the ports and run it
Scratch/gouge is towards the bottom of the cyl, you still should get good compression
lightly sand the piston skirt, Hone the cyl, clean up the ports and run it
