Engine Knock

Discussion in 'Mechanics Garage' started by William Tyler Houston, Dec 2, 2019.

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  1. William Tyler Houston

    William Tyler Houston New Member

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    Hello, I own a 1994 VFR750F. As long as I have owned this bike, it will sometimes make a knocking sound that seems to come from the front left part of the engine. The catch is it only happens within a certain window of the bike heating up. So if looking at the temperature gauge, C = 0% and the point where the coolant fan kicks on being around 50%ish, the knock usually occurs between 25%-30% of the bike warming up. It stops doing it after that point. Anyone have any ideas?

    I will try to remember to upload a video with sound of this happening later.

    Thanks.
     
  2. William Tyler Houston

    William Tyler Houston New Member

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    As you can hear, it is like a chattering sound. It may be hard to tell from the video but it is definitely coming from the top left side.
     
  3. Allyance

    Allyance Member

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    Sounds more like a valve ticking, higher pitch than a bearing knock. Going to be hard pin down if only happens for a short time. Hopefully some one with the same vintage bike can help.
     
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  4. William Tyler Houston

    William Tyler Houston New Member

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    I would also like to add that the noise goes away above 1500 rpm.
     
  5. Captain 80s

    Captain 80s Member

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    Could just be some valve lash that quiets after getting to operating temps.

    Also, get a stethoscope and take some body work off. Sometimes you can use a wood dowel to pinpoint noises too.

    If it doesn't get worse under a load I doubt it's a serious knock. But video is not the same as being there. Chances are if anybody else except the owner that listens to it every time would say you're fine.

    But the only way to know for sure is to start eliminating possibilites which means probably starting with a valve lash check and inspecting everything while you're in there.
     
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  6. Captain 80s

    Captain 80s Member

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    Also try pulling in the clutch next time and see if it changes. I have some Hondas that have some clutch basket rumble that doesn't sound like that's where it's coming from and can make you think it's something else (worse).
     
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  7. William Tyler Houston

    William Tyler Houston New Member

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    Pulling in the clutch doesn't seem to make it any better or worse. I've never done valve work before but I am not afraid to get in there can give it a shot. Maybe when it gets a bit colder (January) I'll take some time to take it apart and inspect/adjust the non typical stuff. Still hoping though someone here has heard this noise before and can tell me what they did to fix it; that would be too easy though. :Help:
     
  8. Thumbs

    Thumbs Member

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    My first thought would be put some flushing oil through and see if that makes any difference
     
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