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Are engine rebuilds expensive? :(

Discussion in 'Technical and Troubleshooting Torque' at netrider.net.au started by n2o_spark, Jul 27, 2009.

  1. Hi
    First up, i'm a newbie. Still an L plater.
    OK so here's the story:
    This morning my bike's engine was a little hard to start, it didn't seem to crank over very quickly, at first i thought, maybe i need a new battery... anyhow... When i when to go training, it was harder to start, and when i left training, it was harder to start again... so i thought, yep battery needs replacing. I stopped for coke at the local shop, and it wouldn't start. i had to push start it :( and i also had to do the same when i left my friends house..

    so here am thinking i need to buy a new battery tomorrow, or at least check to see if my battery fluid level is ok. And i'm cruising down the street, stopped at the lights to get onto the highway, and the bike stalls. it doesn't turn over. and i tried to push start, and that failed.

    I push it to a car park and notice that when i tried to push start it the rear wheel doesn't spin at all.. :(

    So now i'm thinking CRAP... my engine has seized up.
    Call a friend to get a lift home, leave my bike in the car park, and will call someone tomorrow to take it to a repair shop :(

    Does my Diagnosis of a seized engine seem right? ( bike rolls in neutral )
    Then my next question is:

    Has anyone with a ZXR 250-C had a full engine rebuild? and how much was that? cause that's what i'm thinking it will need, perhaps new pistons and rings even, hopefully the bore's not scratched :(

    It's probably not worth it in the end, and i should just scrap it perhaps
    3k bike with damaged fairings, though i've got new ones that iv'e not put on yet, that i could sell at least...

    i'm so sad :(
  2. Was there oil in it?
  3. yeah plenty, over half full according to the sight window, and to be sure, i check it again after it stopped.

    ok now here is the really confusing part.

    after making this thread, i asked myself how can an engine seize and i came up with these options

    1) hydraulic lock - somehow the carbies dump way too much fuel in at idle ( never happened before... and one of the cylinders locks..

    2) unequal expansion - The pistons expand faster than the the block, causing friction and seizing the engine, this would most likely score the bore, fcuk the rings, however once cooled the engine should start with major power loss

    3) a valve drops - the engine drops a valve, and it seizes the engine, a tapptey noise however would have been observed, and the engine will not turn over

    4) catastrophic failure of numerous parts resulting in instant failure and seized engine...

    ok so 30 minutes has passed so i think, well i'll drive back and see what happens when i try to cold start.

    i try the electric start.. kinda ticks over, but like the battery is dead. a good start however as the engine is turning over :D

    so i push start it, and it works!!!!

    i then let it idle for 10 minutes, if it was problem 2 then allowing the engine to warm up slowly would mean i could limp it home..

    i ride it home with no problems, NONE!! no power loss, the bike pulls like it normally does, and it was like nothing happened.

    i turn it off and try the electric start again at home... and it doesn't tick over. lol

    Anyone else got any ideas?
    If it was problem 2 then i'd imagine i'd a a noticable power loss and a screwed engine...?

    it is possible for problem 1 to occur?
    sure it can happen with injectors.. but a carby?

    i should probably have the engine checked out shouldn't i ?...
  4. Not so fast... sometimes when I try to roll start my bike, it behaves that way. You can't be sure it's seized unless you try it with the plugs out (no compression). I would say it's probably not seized... seizure wouldn't happen in a situation like that.

    Probably your electrics. Pull out your plugs first, clean and gap them. That will let you test the above also.

    I've never heard of anyone seizing a 4-stroke engine outside of competition (unless they ran out of oil).
  5. i was hesitant to come to the seized conclusion, however when later when i returned to the bike, and it started, it push started at lower speeds than i tried b4, and the wheel actually spun...so obviously not a proper fcuked engine...

    but electrics would not stop the rear wheel from spinning when trying to push start it earlier at running pace

    VERY weird. I'm no motor mechanic, and the only thing i can think of is hydraulic lock. IF a carburetor can actually dump that much fuel... at random .... :?
  6. I had a GS500 engine replacement done for around $1200. Water cooled may be more expensive though(?).
  7. How was it running a minute before it stalled? To get fuel in the cylinder you need a stuck float needle and a leaking tap. Both are quite possible, so it's not as hard as it seems.

    Also what gear where you trying to jump start in?
  8. I'd be looking at the starter and sprag clutch.
  9. Yeah I had a car once where the start misaligned. similar problems to above.
  10. bike was running fine before it stalled.

    i was trying to push start it in first ( which worked after the break )

    I'll check the starter, seems like a good idea, but can the starter seize the engine?

  11. No a starter's sprag clutch/gear can jam the gearbox (most bikes start through the box)
  12. so what your saying is that it COULD be the starter?

    cause what i'm imagining is that if the sprag jams's the gearbox, then when the bike is in gear, the starter would not allow the engine to crank over.
    However would it still Jam the gearbox when in neutral?
    because the bike would still roll naturally, when either the clutch lever was pulled in, or the bike was in neutral.
    Because the battery was kinda flat, it would not turn the engine over..

    HOWEVER whilst sitting at the lights idling i can not imagine how the starter motor could just engage and stall the bike...

    The most Confusing and perhaps troubling part is the intial seizing of the engine AND then when it would not turn over, via starter motor, or push method.
  13. thanks

    cause it started up again, i'm not really sure what went wrong, however, that guide is awesome, and i probably should get a rebuild, as it suggests
  14. fuel blockage?

    if its the batt do the lights die or dim? does it stop turning over. could mean a dud alternator/startor motor n its not charging the batt

    whens the last time it went for a service or oil change? whats teh colour of the oil

    based on what you;ve said there can be a million things wrong. dont jsut go for the conclusion that its a seized engine
  15. well from what i had tried initially. The symptoms were that of a seized engine...
    last oil change was just over 1000k's ago, and i'm about to go and check the oil for particle matter now.

    Not being able to push start the engine when the it died, cause the rear wheel won't physically move at all, is a good sign that something is seized. At the time, without even seeing that good trouble shoot guide you postted, i had done the first part, and the wheel would not turn when in gear. but was fine in neutral.

    The electric start seems to be another issue, so i'm going to check the battery now, and see what that's like.. will report back on the electric start and whether there is metal in my oil later...

    Nothing anyone has posted has offered insight as to why the engine fully seized up in the first place, then magically unseized after i left the bike for 45+ minutes ( with no performance difference able to be noticed ). perhaps no one ever will be able to explain this?
  16. ok

    drained the old oil, no particle matter, only slightly dirty ( as to be expected since last change was recent ) - put new oil in

    tried the electric start, ticked over a few times, but very slowly - flat battery

    check fluid levels of the battery, 1 cell was almost empty, potential issue - topped it up, battery is on charger. ( if it goes flat again, then i can assume issue with the alternator or charging wiring, or battery is just old and needs replacing )

    so since there is no particle matter, i'll assume nothing too bad happened in the cylinders. I'll try starting it when the battery is charged, and see what happens, perhaps do another oil check after a ride...
  17. how was teh oil compared to the fresh oil u put in?

    have you tried to diag to a specific part of the bike which is seized?

    how do u push start it, put in gear and push it or push it with clutch in and slowly release it?

    i found it funny a few times to push start a bike. wouldnt go at all one stage, clicked outta gear and back in and it just went.
  18. old oil was slightly darker, but only slightly so.

    since the bike now runs, it is impossible to try and diag it now to a specific part :(

    i push started the bike by holding in clutch, running for a little bit, jumping on, releasing clutch. or put bike in neutal.. then jump on bike, gear select and clutch release ( and i tried 6+ times when it was 'seized' )

    Apparently i'm retarded- i decided to re-check the batter, while charging and see if it was bubbling, all the fuild levels were low... they just a a little bubble of surface tension around the hole, making them look full.
    -Topped them all up, and the bike starts via the starter, better than it ever has before :-O ( well they'd probably been low for some time )
  19. funny arent you meant to keep the battery sealed? or do u have the non sealed battery