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Thread: Cylinder and piston wear after 46hrs 680mi [2020 300 XCW]

  1. #11
    KTMTalk Member Cactus73's Avatar
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    Default Re: Cylinder and piston wear after 46hrs 680mi [2020 300 XCW]

    Quote Originally Posted by 211 View Post
    I decided to put a pipe guard flange on which meant pulling the pipe. While I was in there I decided to take pics of some cylinder and piston wear.
    Thought I'd share:

    As mentioned [B]Never messed with any PV stuff till just recently including swapping in the red spring but quickly went back to the yellow and two turns in on the air bypass screw which made it a tad bit richer, a little more oil hungry but way more power; again, only a handfull of rides ago though.
    I just reread this part of your post. I don't understand the oil hungry part. The air screw is an air bypass that changes the amount of air that can enter the intake at idle, but it's not much of a change. Once you open the butterfly, it doesn't have much effect at all, if any. It's unlikely you are seeing power gains from an air screw adjustment.
    Last edited by Cactus73; 08-01-2020 at 10:22 AM.
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  3. #12
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    Default Re: Cylinder and piston wear after 46hrs 680mi [2020 300 XCW]

    If you took those pictures at 20 hours the streaks might have looked a lot worse.
    Oil hungry and carbon on powervalve may be related.
    Victor

  4. #13
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    Default Re: Cylinder and piston wear after 46hrs 680mi [2020 300 XCW]

    Look alright to me

  5. #14
    KTMTalk Member Goatse's Avatar
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    Default Re: Cylinder and piston wear after 46hrs 680mi [2020 300 XCW]

    Quote Originally Posted by Cactus73 View Post
    The air screw is an air bypass that changes the amount of air that can enter the intake at idle, but it's not much of a change. Once you open the butterfly, it doesn't have much effect at all, if any.
    It's nice to see someone else with the same viewpoint on the air bypass.

  6. #15
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    Default Re: Cylinder and piston wear after 46hrs 680mi [2020 300 XCW]

    Quote Originally Posted by Victor View Post
    If you took those pictures at 20 hours the streaks might have looked a lot worse.
    Oil hungry and carbon on powervalve may be related.
    Totally agree. I bought a new 150 XC. Never even started it. Took it apart to convert to 200cc. The new 150 cylinder had the same markings, however there were significantly more of them. Apparently due to the short time they run the engine at the KTM factory.
    Over time they all disappear.
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