Is the engine supposed to rattle like that?

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Roostmaster1
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Is the engine supposed to rattle like that?

Post by Roostmaster1 »

Just checked out my first KDX. Cosmetically it needs work but does crank on first or second kick and seems to run out fine. My concern is when it idles it sounds like a connecting rod slapping the inside of a big block Chevy. I’d post a video but it won’t let me for some reason. Is this hard rattling normal? Only seems to sound like that at idle. My yz125 never sounded like that. Please help
kdxsully
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Re: Is the engine supposed to rattle like that?

Post by kdxsully »




Does it sound like this?
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Roostmaster1
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Re: Is the engine supposed to rattle like that?

Post by Roostmaster1 »

Yes, it sounds like that. How do I post a video like you did?
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KDXGarage
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Re: Is the engine supposed to rattle like that?

Post by KDXGarage »

"Full editor"

The play button on the far right of all the buttons above the area in which one types

Youtube link, etc.
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KDXGarage
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Re: Is the engine supposed to rattle like that?

Post by KDXGarage »

Look up "piston slap" on youtube
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kdxsully
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Re: Is the engine supposed to rattle like that?

Post by kdxsully »

KDXGarage wrote: 04:24 pm Aug 10 2019 Look up "piston slap" on youtube
This. That video is with a sleeved cylinder, with about a .35 difference in ring gap from the top and bottom to the middle of the cylinder. A new top end with a correctly spec’d cylinder fixed my issue.

And for posting the YouTube videos, I literally just paste the link and it embeds the video for me. Easy cheesy.
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Roostmaster1
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Re: Is the engine supposed to rattle like that?

Post by Roostmaster1 »

This one sounds really bad. My first thought here was piston slap but I saw a thread on here where the guy actually figured out his was a bad main bearing. Sounds like it could b either one and the only way to find out is a tear down. The dude n the other thread said his was running fine other than the noise. This seems to b the case here. Can someone post a video of a fresh engine idling and revving?
kdxsully
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Re: Is the engine supposed to rattle like that?

Post by kdxsully »



This is after I did the cylinder and piston. This is an air cooled with no powervalve too though
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