No announcement yet.

Piston damage descriptions

This topic is closed.
  • Filter
  • Time
  • Show
Clear All
new posts

  • Piston damage descriptions

    I took some shots of pistons from this morning's incoming cores to show you some typical damage:

    Normal wear, but broken locator pin and ring:

    Improper break-in

    Notice the blow-by under the rings all the way around. Proper break-in only has slight blow-by under the ring-gap:

    Overheat (4 corner seizure):

    Water Ingestion

    Notice the nice clean underside with the wide gouges all around:

    Forgiegn particle:

    Detonation (due to too-low octane gas, too-high compression, slight air leak, too-lean carb settings, clogged fuel filter, etc.

    Notice the damage right in front of the exhaust port - a sure sign:

    [ April 06, 2002, 09:59 PM: Message edited by: Bryan Glynn ]

  • #2
    Melted piston top (due to wrong heat-range spark plug, massive air leak or massive fuel starvation):

    Lack of Lube: Note the heavy vertical gouging and dry, burned oil on the underside from excessive heat. The crank rods and bearings may also show blueing.

    Last edited by Technical Support; 03-31-2005, 04:03 PM.


    • #3
      The melted piston top looks like what happens to the Polaris domestic motors that have the single mikuni pump that starves the triple for fuel. All you Polaris owners better get the second pump on there or this could be your piston in the future...


      • #4
        The melted piston due to a massive air leak or fuel starvation looks exactly like the one I got out of my #1 cylinder from a '98 STX 1100 with 64 hours on the clock...

        Could there be the same kind of problem with the Kawasaki as on the Polaris? It is also the cylinder furthest away from the pump...

        In tearing open the carbs, I did not separate them. Could there be a problem inside the line bringing fuel to the #1 carb?

        It seems to me these engines ought to be bullet-proof. Yet the reality is that I hear about them breaking on a regular basis... I find that disturbing, honestly...

        GREAT PICTURES! Awesome article, Bryan.
        No more Jet-Ski's for this boy...


        • #5
          Re: Piston damage descriptions

          Is there anyway to tell from those pistons/any pistons if a particular watercraft is running too lean or rich?


          • #6
            Re: Piston damage descriptions

            Re-read, it already does.
            SBT Tech Support is here to help with your problems.
            We try to answer each question quickly and accurately.
            Please do not use Private Messaging for Tech Support, use the forums.