I might be detonating?

Discussion in 'General Questions' started by Frankenstein, Aug 8, 2016.

  1. Frankenstein

    Frankenstein Active Member

    How can I tell if I'm detonating? Like does it sound like something in particular? I can hear an almost crackling sound at very high rpms. Like popcorn popping, but with the sound of crunching glass...

    Is that detonation? The sound keeps me from going full on with the throttle just because I think it could be damaging..

    Let me know!thanks!
     

  2. jaguar

    jaguar Well-Known Member

    pull the head and look for little spots on the piston or head where metal has gone missing.
    remedy: richen the mixture, retard the timing (offset the key), lower compression less than 130psi
     
  3. Frankfort MB's

    Frankfort MB's Well-Known Member

    Or higher octane fuel:)
     
  4. Frankenstein

    Frankenstein Active Member

    So that doesn't answer too much, what is the sound I hear
     
  5. Frankfort MB's

    Frankfort MB's Well-Known Member

    Detonation
     
    Frankenstein likes this.
  6. CrazyDan

    CrazyDan Member

    Detonation would be the mixture firing from the heat of the cylinder before tdc and before the spark. Make the air/fuel mixture richer and get higher octane.
     
  7. Frankenstein

    Frankenstein Active Member

    Thank you I figured as much...
     
  8. crassius

    crassius Well-Known Member

    a sound like popcorn popping at high revs is often heard for a while in a new motor while the rings are seating - it should clear up as it runs in a bit (back off throttle some when you hear it)
     
  9. Steve Best

    Steve Best Active Member

    All great advice from Jag, Frankfort, CDan and Crassius, I agree with it all.
    A quiet muffler makes the popcorn popping sound more obvious. It is damaging.
    Pulling the head is the surest way to know. Look for little specs of aluminum.
    Like Crassius said, new cylinders and rings seem to do it, was my experience too. I don't know why.

    Steve
     
  10. Frankenstein

    Frankenstein Active Member

    Definitely past the bedding stage, I'll pull the head a bit later
     
  11. CrazyDan

    CrazyDan Member

    I want one of those cool light/eyeball things that doctors stick in your butt to see up there. Would be perfect for checking inside your cylinder without having to tear it down, just pop it through the spark plug hole.
     
  12. Frankenstein

    Frankenstein Active Member

    They sell relatively cheap endoscopes now on the internet, in fact they plug into your phone and the phone is the viewing screen and controls for the camera lol... Even get them 50 feet long if I remember correctly.
     
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  13. Frankenstein

    Frankenstein Active Member

  14. Frankenstein

    Frankenstein Active Member

    Comes with a mini hook too, so when you drop a washer or a screw or a wristpin clip into the engine you won't be forced to flip the entire bike upside down in an effort to get it out!
     
  15. CrazyDan

    CrazyDan Member

    That looks sweet, but not sure if my crappy phone can do it. Imma get ahold of them and find out. Might need a standalone type because I'm not upgrading my phone, especially before I'm completely happy with my bike, which would probably be never :p.
     
  16. Steve Best

    Steve Best Active Member

    4 nuts and 5 minutes and the head is off and I have a great view in full light while you are still looking for the app on your phone.
    Come on guys, if you are too intimidated by 4 nuts, maybe you need a different hobby.
    Since Headsmess put me on to the teflon headgasket trick, it gets even easier.

    Just DO it!

    Steve
     
    Frankfort MB's likes this.
  17. CrazyDan

    CrazyDan Member

    Lol wish it was just 4 nuts, but I'm running an hs 144f. Gotta tear the entire engine apart to get in the cylinder. A butt scope would be far quicker to just take a look.
     
  18. Steve Best

    Steve Best Active Member

    Ah! I understand your pain. Just bend over now and put your hands on your hips...

    Unfortunately I can supply some pictures of what detonation looks like, coming soon.

    Steve
     
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  19. CrazyDan

    CrazyDan Member

    My 144f was pinging a bit when I got it, had it filled with 87. Thought I had a lemon motor but then I figured that the cylinder was bored out a tad but they didn't increase the head size at all so my compression was higher than a 142f. Swapping to 91 got rid of the sound and I didn't see a drop in performance so I assume I was correct. So far so good, but I think I need to look inside to make sure nothing bad occurred while on 87.
     
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