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ZXR 250 overheating issues

Discussion in 'Technical and Troubleshooting Torque' at netrider.net.au started by 87crisis, Mar 26, 2013.

  1. hey guys,

    got a old zxr 250 A ....pulled out a few connections i could get to so as to give em abit of a clean but that doesn't seem to fix the problem

    all started the day after i washed the bike then went on the guard of honour ride for mav where sitting in traffic saw my bike overheat and coolant to piss out of my overflow....when that was done - there was a buttload of steam coming out from the overflows

    since that incident i've noticed that the bike will start to hit the redline of the temp gauge when stuck in traffic...meanwhile the second i start moving it starts to come down ....even noticed that i give the bike a few revs and the needle comes down a cm or so momentarily....can't make sense of that but yeah

    suggestions/thoughts/things that you'd trust a retarded sibling to try and fix this? (i figure the retarded sibling would be about the extent of my mechanical talents.)
  2. Fan working? Power getting to it? Fan switch working? (not temp switch)
    Did you bleed the cooling system after the loss of coolant?
    No leaks? Water pump ok?
    Radiator not blocked?
    Just a few things to check. :)
  3. ok....didn't bleed cooling system....no idea how to (yes i'm that special)
    pretty sure the fan isn't working
    no apparent leaks as i was going over the bike and tightening up bolts today
    no idea about radiator being blocked

    spose i best trawl through the workshop manual for the zxr and flush out the coolant system....might have to finally bust the seat lock to get into the bike

    out of curiousity could it also be a fuse ?
    (can't open seat...so can't get to fuse box.)
  4. my ms's just said it's because my penis is too big....i think she might be onto something.
  5. Dreaming??? Wake up & ask her again!! :LOL:
    Could easily be a fuse, switch or just a connector.
    See if you've got power to the fan when it's hot. Got a test lead? ($10 at Supercheap)
    Also, try putting 12v to the fan to make sure the motor isn't burnt out.
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  6. Nothing wrong with her sense of humour at least.
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  7. well when your bike got scared in traffic the other day, the coolant seemed to be nice and fluro with no signs of rust, so the coolant circuit at first guess is clean.

    its not your radiator cap, the pressure spring seems to work
    its not your hoses, otherwise it would have come out there instead.

    it could be:
    thermostat, might not be opening early enough. when you rev the engine it opens a little...
    thermo fan switch
    broken wire

    unplug the fan and hook it up to 12V. this can be from the bike, battery or PSU.
    this will tell you if it is the fan.
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  8. cheers man will get ontop of it in the next day or two
  9. will aim to test most of this (hoping it's not a thermostat issue and a basic electrical one if anything)

    will also tackle my first coolant flush at the same time...might also change over my brake oils whilst i'm busy playing mechanic hero.
  10. OK so a few things have happened since I started this venture into actually doing some work on a bike for once
    none of which are really related to the radiator or fan all that much

    there is a paranoid possibility that I've got a cracked head gasket

    for the first time since owning the bike I finally figured out how to get the front seat off after busting open the rear seat as the lock was seized....so got all the fairings off and one of the first thing's I've realised is that the coolant reservoir is bone dry

    spent spare time yesterday doing an oil change and thankfully the old oil seemed fine without any milky residue around the cap or in the oil itself

    my next actions are going to be flushing out the radiator and removing/inspecting the thermostat (plus more than likely having my first attempt at making my own gasket for when I put the thermostat n housing back in place) before refilling with coolant

    after that's done i'll be testing electrical supply to the fan (sure I could try doing this first but the radiator needs flushing n refilling regardless.) and troubleshooting whatever issues I come across there

    hopefully if I come through the end of this without a busted head gasket then i'll be making another thread for me removing & cleaning out the fuel tank of rust although something tells me that i'll be needing to change the head gasket to be safe rather than sorry so i'll also create another thread for that

    thanks to all here and @1600Nomad @Fridgy35 @tiprat and anyone else that has helped and apologies for highjacking the other thread i'll try to keep it in here from now on and i'll also try and keep this updated with a few photo's of my progress.
    • Like Like x 1
  11. Too easy bud, if I was in sideyenee I would be over giving you a hand/moral support
  12. @Hubby schooling me ....thankyou sir - just adding it here as i'm trying to keep it in this thread from now on so if other's need help in the future they can use this thread and learn from my stupidity and the wisdom of NR ....

  13. it's the fan switch (y) had to fill radiator JUST over 500ml to get it topped up so no real issue there either...
  14. i was gonna say... of course the reservoir was empty, it got hot, overfilled the reservoir, pissed it all over the ground, then when it got cold, it sucked back what it didnt piss away.

    and as i said, the coolant looked nice and sickly green, you prob dont need a flush. not saying dont do it (of course with most maintenance type things, its good to do every now and then) but i wouldnt put it on your 'needs to get done very soon or the world will end' list, it sounds like that is big enough already.
  15. It's alright i've retired the zxr from the road for 3 weeks (end of rego why register something i dont need to when i can pay other bills in the meantime) plus being such an old prick of a bike and seeing some of the corners previous owners have cut with this bike (like over-run from the paintjob set in the bottom of the petrol tank ? come on guy ! ) so i'm gonna pull this sad sack of a bike back into some respectable state (y)
  16. refilled coolant just before (had no soft water so just picked up some premixed coolant from woolies) and seen some moisture spitting out along with some white smoke initially

    this concerns me and kicks my paranoia into overtime - im thinking it's just a case of it being colder (7pm on a colder than normal night) but will be checking my oil over the next day or two and giving her a quick run in up to the olds just to see how she handles and then check the oil again/keep an eye out for any continuation of that white-ish smoke i saw briefly.
  17. The moisture is more than likely condensation in the exhaust.
    The white smoke possibly slightly overfilled oil?
  18. Oil is blue smoke, overly rich mixture is black, white is water. If it's only briefly it might just be condensation in the pipe, but it's also possible for a bad head gasket to suck water without contaminating the oil or even blowing back into the overflow bottle.
    You can check for it by filling the cooling system and marking the overflow then running it up to operating temperature and shutting it down. Repeat a couple of times if you want but if you check the plugs once the bike cools down and they're wet you have a stuffed head gasket at the very least. You may also need to bleed the system. Any air pockets will expand when the motor heats up and push coolant out of the system and create hot spots but then suck it back in when it cools.
  19. +1 to needing to bleed it *shakes head* kinda skipped that when running it for a minute or two earlier - will do in the morning
  20. just turned to the ms's and said the guys have reminded me that i need to bleed the coolant system forgot about that

    she replied with "is that before or after you smoke all their cocks?"
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