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She's dead, Jim

Discussion in 'Technical and Troubleshooting Torque' started by momo, Apr 24, 2008.

  1. My bike had been sounding kind of ill for a month or two - it sounded like a tractor up to about 4-5k RPM, and there was increasingly a sort of clattering noise at low RPMs. A few days ago, it finally died in the RNP. It had been down on power a bit that day and the engine even noisier than ever, but when I hit 18k on the last straight before the ride down to weir, it all went to shit. I suddenly lost all power, it wouldn't rev over 6k (I guess that means I lost one or more of hte cylinders?), and the motor/clattering suddenly became deafeningly noisy. I limped it out of the park (so glad I got it back up the hill to the entrance), but it kept stalling and I couldn't restart it at the lights.

    The thing that made me curious is that I noticed that, even in neutral, when I rolled it back and forth there was a loud clacking noise. I could just be a complete noob, but I thought the engine was effectively disconnected from the wheels in neutral, so is it possible that I've either farked something other than the engine, or that I've farked the engine as well as something else?

  2. Probably rooted the lot.
    Since bikes share the oil with the engine and 'box then if something let go in a big way in the engine then fair chance big chunks of that could have got into the gearbox and be rattling around in there (causing all sorts of damage).
    This is why you don't leave a problem until something goes bang.
  3. Well that sucks :oops:
  4. On a 16 year old 250 that's already showing signs of severe distress???

    Serves you right.

    Buy a pushbike, and retire before the motorcycling gods smite you with some dreadful plague.....
  5. that's some christian magnanimity. Seriously, though - I thought I had a bad leak around the headers or something, and I was planning to take it to a mechanic ASAP. Revving the tits off it in retrospect was obviously a bad idea, but it didn't seem on death's door.
  6. Woop, rooted. :(
  7. noo don't say that :( say it is going to be fine and a mechanic will make it all better for $100 :( i love my bike :(
  8. I should have put a bit of a grin at the end of my last post, but one of the great arts you need to have is mechanical empathy; when a device is clearly labouring, you need to be gentler, not more severe.

    The modern Japanese engine is a robust device, but I fear this one, by your description, may have shuffled off the mortal coil and joined the choir invisibule. Tomorrow is a Public Holiday, but Saturday morning I'd start ringing around some wreckers to see if you can rustle up a replacement.
  9. That's what happens when you join the green team ...

  10. You've thrown a rod by the sounds of it. Find a replacement engine, or push teh bike off a cliff and collect insurance.
    Teh clattering was most likely rod knock, the clearances grew, hammered teh rod cap and it's bolts, and one finally let go when fatigue set in.
    Next time, buy a Vespa.

    Regards, Andrew.
  11. Can anyone say 'new boat anchor?'
  12. it is now worth a grand total of $50, and that's optimistic.
  13. I went to youtube and looked for some videos of rod knocking - yeah that's exactly what it sounded like. Shit eh :( I guess it's replacement engine time, because that would still be a lot cheaper than looking for another one.
  14. Yeah I saw that. I'll try some of the Sydney wreckers, because the that seller always has ridiculous prices.
  15. Cheers for that :D 22k km isn't bad, I should be able to bring him down a bit.
  16. What a thrown rod looks like :)



    And if only it cost me $1k :LOL: :LOL: :LOL: :LOL:
  17. What was that in?

    What was the reason? Could you see what else failed, to take it out?

    All the best

    Trevor G
  18. Actually, U Tube aside, that is really called big-end knock.

    As cejay's pic points out if a conrod fails, it breaks and exits the crankcase, at which point the engine will no longer run. Or even crawl.

    The big-end is the bearing at the bottom of the rod, and that could have worn out. People sometimes describe that as "throwing a big-end".

    Worn timing chains and/or tensioners can also develop a very loud knocking noise, but that is not quite as blatant as when the big-end goes.

    It has a particularly troubling "klank klank" to it, whereas the timing chain or its tensioner is more "krung krung"

    All the best

    Trevor G