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ZZR250 loud knocking, losing coolant

Discussion in 'Technical and Troubleshooting Torque' started by Snowman, Apr 5, 2009.

  1. Hi, I was riding my bike today and it started making a very loud knocking noise so i stopped and then it started leaking coolant from the engine, just trying to figure out what it is and if it is safe to ride it home about 5ks and maybe how much it will cost to fix.

    - the noise still happens when the clutch is pulled in
    - i can feel a slight throb in the foot pedals at the same time as the noise
    - there doesnt seem to be any power loss or surging
    - temperature was still good even after losing most of the coolant

    thanks for any help

  2. Loud knocking noises in ANY engine are NOT a good sign!

    First of all, whatever the cause of the noise, if the bike has lost its coolant you should not be riding it any distance.

    Now, where is the coolant leaking from?

    You say there is no power loss; see above, you should not be running the engine at all until you ascertain what has gone wrong.

    Temperature guage means nothing; in many engines when all the coolant
    is GONE, the guage shows normal.

    My guess is that you have overheated the engine and blown the head gasket, or that there is a leak in the thermostat housing and you have kept riding it while it has been pumping the coolant out.

    Either way, it's mechanic time :(.
  3. really not sure where the coolant was coming from but it kindof looked like the right hand side of the bike. i looked through a hole in the fairing and it may have been coming from a seal in the engine near the top.

    had a funny feeling it was mechanic time :(

    glad it lasted till i got my P's at least.
  4. Don't despair, it may not be terminal, but it may not be cheap to fix.

    Just don't start it or try to ride it.
  5. its currently sitting in a hospital carpark close by, ill try and pick it up tomorrow if i can.

    the bike only cost me $2000 all up so if its too much to fix i may just buy a new one or wait out my P's and buy a bigger bike

    it only has 35,000ks on it tho, i thought it would be trouble free till about 50,000

    thanks for your help
  6. Two factors at least could be in play here.

    How well and how often was it serviced, properly, not a quick-and-dirty oil change at home, before you bought it?

    How well and how often has it been serviced since you got it?

    Have you added coolant to it at any time since you bought it, and if so, did you use water, or proper coolant, suitable for alloy motor castings?

    And, I guess, how have you been riding it, although that is the least likely cause of the problem you seem to be describing.

    Keep us up-to-date anyway, and if a local Netrider can help, I'm sure someone will volunteer.
  7. could be the seal to the water pipe in the top of the head.. thats about 50c. take a pic and post it of the leak if you can.
  8. fixed the knock!, it was a loose bolt on the rear disc smacking the caliper as the wheel was spinning. its still losing coolant though could that be a related problem? im going to pull the fairings off tomorrow and see if theres a leak somewhere. the bike doesnt seem to be overheating, just steaming from the coolant leaking onto the exhaust. ill post pics of what i find tomorrow, thanks for your help guys!
  9. Snowman, if its leaking coolant don't ride it until you've fixed the problem, otherwise you will fvck it very quickly. The fact that the temp gauge may not be very high does not mean much. The temperature in the cooling system is held down as the coolant boils off, but critical parts of the motor may already be cooked. The hottest parts of the motor are near the top and if the coolant level is low they will suffer.
  10. woo! problem solved, me and a friend stripped all the fairings and tank off today and found a leak in the hose from the thermostat (i think) into the top of the engine, replaced that and topped up coolant now its going great.

    I just think its weird having two different problems happen at EXACTLY the same time, both of which i thought were quite serious but in the end cost me nothing to fix.

    this little zzr is teaching me a lot about fixing bikes lol.

    again, thanks heaps for all the help.