Ninja 250 Issues

Discussion in 'The Garage' started by Elle2Konsai, Feb 10, 2018.

  1. trc.rhubarb

    trc.rhubarb ZoomSplat!

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    While rebuilding a ninjette I picked up that had been stored uncovered in the backyard for 10 years, one of the many issues I found was that the end of the plug wires at the coil were nasty. I trimmed about 1/4" off each and that made the difference. Also the resisters in the plug boot were corroded, so I removed and cleaned them. You can check these things with an ohm meter. All you need is in the ninja FAQ
    https://faq.ninja250.org/wiki/Ninja250_Howto

    I used a timing light to diagnose a coil that was cutting out. It wasn't the coil though, it was a worn through wire under the tank.

    Likely that air filter has disintegrated - a couple years and they turn to powder.

    There is a tiny fuel filter in the gas line where it connects to the clutch side carb. You can't see it but it's in the line and if it's clogged, would prevent revving.
    Speaking of fuel, a crankcase full of gas would also cause it to not run right. Open the filler and take a whiff if you can't tell from the sight glass.

    Did you buy it from a guy named Justin by chance? I knew I remembered reading this issue once before... https://www.ninjette.org/forums/showthread.php?t=116053

    There is really little to these bikes, so I'm confident you will find the issue quickly. Valves are super easy to do and oddly, I didn't find an issue with the space. Check out the timing chain just because you're in there... likely not an issue but if it's not in alignment, I can see it running sort of but not properly.
    #21
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  2. Elle2Konsai

    Elle2Konsai Squid

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    Hahhaa, that's just brilliant. Well done and giving credence to the nature of true adventure bikes as they started....whatever bike you had in front of you :)

    Thank you for the suggestion and sharing your experience. I will check this and add it to my long list of possible causes that the inmates here have generously shared with me.

    Love that!


    On a more general note, I have the bike apart not quite where it needs to be but getting there. I might have spent more time writing notes to myself, dog-earing notes, and taking pictures so I can sort of remember where it all goes.

    Next step will be to get myself some actual tools like a decent adjustable socket/wrench set (i've been using some $9 screwdriver set with a few attachments from walmart) to remove the radiator mounts and open up the valve covers. I guess i'll need some gauges too if I'm to measure the valve clearance.

    I figure I may as well do this part first as it probably is needed given the mileage on the bike. Then if I miraculously manage to do it right then i'll try the vacuum leak identification, followed by the spark plug & wire inspection, and then try starting it up and seeing if and how it runs. Only then would I try something with the carburetor as those truly are mystifying to someone like me for whom the pinnacle of their wrenching exploits is an oil change...
    #22
  3. ex250mike

    ex250mike Been here awhile

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    I had a co-worker whos bike "broke down." He tore it apart trying to figure out what was wrong. It was out of gas...

    Normal diagnostics procedure is to check the easy things first. IE. if your computer dosen't work make sure its plugged in!
    You jumped in head first.

    I reccomend getting a set of JIS screwdrivers. You'll eventually strip everything out using phillips.
    #23
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  4. FL Pepper

    FL Pepper OMGWTFFTW

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    Whoa, slow down there lady. Valve adjustment on a non-running Ninja 250 won't get you anywhere. Fix what's broken and then you can tune it for optimal performance. Most of these bikes will run forever without a valve adjustment, just not well at times. If you do a valve adjustment you will need a 9mm deep socket, a torque wrench, some feelers gauges and a method for syncing the carbs afterwards. None of that is difficult but can be a little stressful the first time.

    Not sure why you are removing the radiator mounts.

    Definitely get some JIS screwdrivers. You will need them for the many times you take the carbs apart before you get everything cleaned.

    I would definitely start with the easy stuff. Check your clutch cable. It may be frayed on either end. Adjust it if it is not frayed, replace otherwise.

    You may need to clean your carbs. It does not take much to clog those tiny jets. Buy a rebuild kit first, as long as you are going in there.

    All you need to know can be found here: https://faq.ninja250.org/wiki/Ninja250_Howto
    #24
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  5. lnewqban

    lnewqban Ninjetter

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    As others above, I advise against attempting valve adjustment first.
    The reason is that it cannot be the cause of a sudden change in performance of the engine, like the one at hand.
    If the current gaps of the valves are too small, the engine would have never started up due to insufficient compression.

    In other words, the adjustment may be needed due to mileage, but it is not a priority.
    The work seems to be simple, but a person without experience could create additional problems in addition to the one currently impairing the engine for real.
    It is easy to drop a little part into the well of the timing chain, or improperly install the tensioner, or induce a chain jump out of synch, or end up with wrong valve's gaps (access of the gauge and achievement of fine feeling is cumbersome).

    Additionally, if one ear of the rockers inadvertently gets cracked, as the article in the following link explains, a catastrophic failure will follow:

    http://n4mwd.blogspot.com/2013/

    Again, think of things that have happened since you bought the machine and test the easy potential causes of the problem first.
    You need a running engine, even if marginally, before proceeding with the fine adjustments of valves and carburetors.

    :muutt
    #25
  6. Bigger Al

    Bigger Al Still a stupid tire guy

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    Shims will not be of any use in an engine that uses screw-and-locknut adjusters. The special tool from Kawasaki is a help, but not essential.
    Cleaning the carbs is a good idea, as are most of the suggestions given so far in this thread. 250 Ninja motors are peaky little things, and as such the valve adjustment is crucial to getting the most that the 27 ponies have to offer. My wife's bike would start up just fine, run decently until warm, then race at idle once at operating temperature. Nothing that I did with the carbs changed the symptoms, and it took a valve adjustment to make it run properly. The exhaust valves were all very tight, and leaving them that way would have eventually led to some not-so-good results.
    The OP needs to be applauded for jumping in with both feet, and for having the presence of mind to ask a lot of questions. I'm of the opinion that knowing one's motorcycle inside and out adds greatly to the experience and satisfaction of ownership.
    #26
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  7. FL Pepper

    FL Pepper OMGWTFFTW

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    Thanks Bigger Al for correcting my mistake. I meant feeler gauges, not shims. Wrong term.
    #27
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  8. Bindlestiff

    Bindlestiff Been here awhile

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    Maybe the OP can clarify, but my understanding is that the bike is running, it's just bogging down when accelerating in gear. I'm not saying the valve adjustment is for sure going to fix it, but these bikes seem to be extremely sensitive to tune up issues, so I definitely wouldn't go really digging into the carburetor or anything like that until you know the valves and carb sync (and plugs) are at least close to correct. I'd certainly keep an eye out for vacuum leaks or loose or corroded wiring in the process though. (And if it is a vacuum leak it'll become very apparent when doing the carb sync.)

    The service manual says to remove the radiator to get the valve cover off. I've found you can do it by just removing the cooling fan, but it's a tight squeeze. Having the radiator off also gives you more room to work on the exhaust valves. A 15 year old bike with unknown service history could probably use a coolant change anyways.
    #28
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  9. trc.rhubarb

    trc.rhubarb ZoomSplat!

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    No need to remove the hoses, just the radiator.
    #29
  10. Bigger Al

    Bigger Al Still a stupid tire guy

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    It's all good. Everybody's just trying to help, which is one of the very best things about ADV.
    #30
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  11. Elle2Konsai

    Elle2Konsai Squid

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    I'm always flattered and appreciative of all the advice given here so please accept my thanks. And while I'm on that subject, I hope you'll bear with some of my ignorance on the subject. My engineering degree is in software after all so feel free to ask me about synchronization and dead-locking :)

    So there is one big thing that stands out to me with this situation and which differs from other issues I have experienced during my time as a rider with various bikes. Previously I owned a motorcycle with a carburetor and after so many issues I swore i'd never have one again. Had it not been for the need to obtain a complete beginner bike for a family member, I'd never have such a bike again.

    With that bike, it was an XT225, I experienced the bike cutting off at a given RPM but it was very different because the motorcycle was stumbling, coughing and sputtering if you will. The ninja 250 doesn't do that at all...it doesn't sputter or feel like it is gargling gasoline. Instead the moment the Ninja hits 4k rpm's, even in neutral, it quickly shuts down. It doesn't die instantly but the revs rapidly drop (in the span of a second or two) and it will then shut down.

    Call it beginner's mind or whatever zen concept fits but could this all be due to a failure somewhere in the spark side of the spark + fuel + air recipe that ICE's need? Perhaps a spark plug or spark plug wire or maybe a coil pack?

    The reason I thought of the clutch initially is that a) the the friction zone was very high on the bike from day 1 and b) the first manifestation of the current problem(s) was coming back from a ride the bike refused to rev past 4k rpm's in about 2nd gear but it didn't die immediately and also the engine kept making noise....so while I've never had a clutch go bad on a bike I have experienced it on a car and that felt like a slipping clutch. However the next day I got on the bike it wouldn't go past 4k rpm's again even in first gear and it began shutting off....which certainly doesn't seem like a clutch issue even if the lever itself may need adjusting or if the clutch has got some wear on it.

    Re....valves, I'd like to learn to do this myself but I am grasping the takeaway from many of your comments that valve issues don't magically appear overnight or suddenly.
    #31
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  12. trc.rhubarb

    trc.rhubarb ZoomSplat!

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    You may check to see that you have the stock CDI - located on the clutch side about where a passenger would sit under a rubber strap.
    There is a device, BRT-TIS which wasn't that popular here but apparently elsewhere that allowed custom revlimiter settings. It's possible it's set to 4k either as a joke, for an ultra-new rider or that it's broken.
    If the bike otherwise runs great but just stops like it hit a revlimiter, it's worth checking the CDI either way. If you have a timing light, you can see if the spark cuts out.
    More likely is that one of the coils is dropping out under load which you can also see with a timing light.
    #32
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  13. lnewqban

    lnewqban Ninjetter

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    I have experienced a similar behaviour when having some water in the bowls of the carburetors and when a rag accidentally restricting the airbox intake.
    The flow of fuel or air could be restricted, killing the internal combustion at the intake flow corresponding with @4K rpm's.
    An intake mix with too much air or too much fuel in it completely and suddenly kills the combustion and the engine cuts off by itself.
    If only one coil or spark fails, the engine delivers less torque, but it keeps working (this also happened to me).

    An electrical sudden failure, which gets fixed by itself after the shutdown, is rare in my opinion.
    Other than an odd CDI cutoff, as explained by trc.rhubarb above, I can only think of a main contact that gets temporarily disconnected by the vibrations at 4K rpm's, such as a fuse, the ignition switch, safety switch (there are three of those) or the kill switch (red big toggle switch by right hand grip).
    #33
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  14. FL Pepper

    FL Pepper OMGWTFFTW

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    I'm still going with the carbs. Based on the OP's description on another thread of the way it was running, sounds like clogged jets. Gas starts to go bad pretty quickly and the Ninja 250 carbs are notorious for those tiny holes in the jets getting clogged up.
    #34
  15. trc.rhubarb

    trc.rhubarb ZoomSplat!

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    Thing is, the jets responsible at higher throttle openings are the bigger ones... if anything clogged, I'd expect the pilot circuit to go first.
    Without more info or some testing feedback, it's all just shots in the dark.
    #35
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  16. YJake

    YJake PAR Nation

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    We ADV'd ninjas before ADVing ninjas was cool.
    IMG_3298.JPG

    -Jake
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  17. islandtosh

    islandtosh Been here awhile

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    Lots of good advice. Since the bike is apart, get the battery tested (or at least hook it up to a charger).

    My bike had similar symptoms, and it didn't resume running right until I fixed a vacuum leak. Caused by me. Turns out that when putting the carbs back on, I popped off one of the little vacuum hoses that plug in near the fuel inlet.

    Sent from my XT1096 using Tapatalk
    #37
  18. lnewqban

    lnewqban Ninjetter

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    Still not working properly?
    #38
  19. ex250mike

    ex250mike Been here awhile

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    If not I'll buy it for $500.

    I miss my old ninja.
    #39
  20. JohnCW

    JohnCW Long timer

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    I'm assuming your must be TOTALLY confused by now.

    The bikes 13 years, and with the low mileage it has obviously spent a lot of time sitting unused. ANY bike like that will need the carburetor/s cleaned out, that is just a given. So ........

    (1) adjust the clutch, (2) remove and give the carburetor/s a basic dismantle, clean and adjust (no fancy method needed), and (3) check the petcock filters are not restricting fuel flow.

    As you say, you don't have the mechanical experience, and a carby overhaul while not difficult is probably something best left to others, so pay someone, they are not big jobs. Adjust clutch 5 minutes, clean carbies (no idea how hard they are to get off a Ninja 250 but lets say 2 hours tops), check fuel flow 10 seconds. So a total of about 2 hours work, no parts required (yes they can just reuse the float bowl gasket).

    P.S. and an oil and filter change. That's another reason the clutch may be hanging .....dirty old gummy engine oil.
    #40
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