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1990 Honda CBR 250 RR - running ("spitting") issues

Discussion in 'Technical and Troubleshooting Torque' started by Doubled, Dec 5, 2011.

  1. Good Morning/Afternoon fellow riders,

    I have been 'trolling' this forum for quite some time and have posted a couple of times over a period of time now..but it has come time to post a problem ive been having recently with my bike.

    I am currently having an issue with the 1990 honda cbr 250 RR i own.

    I have been noticing this problem for a month or so now (when i do get the chance to go for a ride).

    Ill describe the problem as best i can but it may be a little more difficult not being hugely mechanically minded (im trying to learn by doing alot of my bike stuff myself before going to a mechanic)

    The problem-o: issue does not occur after initially starting or running the bike (i always let it warm up before going for a ride). I have noticed after a extended period of time riding (maybe 30mins+) that my bike starts to...so to speak 'spit'.. when keeping a constant and even throttle (for example through a corner)...the problem is that the bike starts to spit, as though i was jamming the throttle open and closed (back and forth / jumping forward and backwards)...this can obviously be very dangerous when going around a corner at a fair speed and is becoming a frustration when riding at a constant speed..

    I wish to try and resolve the issue as soon as possible before a accident occurs and i am hurt..

    I was wondering if anyone else has ever experienced this problem or knows where the problem may lay lie so that i can order any parts necessary and attempt to amend this problem.

    Any help is greatly appreciated..

    Best Regards,
  2. Update on the issue..

    Riding to work this morning i noticed my bike doing the same problem...'spitting' once more and making accelerating extremely difficult...i also went to take off from the lights the bike cut out..
    Luckily this happened 2minutes from my office and i was able to push the bike the rest of the way..

    I am going to give riding it home ago later..however the problem was that when i was releasing the clutch and applying the accelerator just as the bike got to clutch point it would almost cut the engine out (with me just catching the clutch in time for the bike not to stall).

    Please if anyone has any ideas as to what this problem may be it would be greatly appreciated otherwise i will have to go to the bike shop and explain my problem to them sounding like an absolute knob explaining it as best i can with words like 'spitting'...

  3. Sounds like a miss to me. Have you checked that the spark leads are firmly pressed on. If that doesn't change anything, pull the spark plugs out (1 at a time so you dont forget where the each lead goes) and check if they need replacing.

    Give it a try and let us know.
  4. My first thought is a fuel or spark issue. The old CBR250s are a really highly strung engine, so fuel, spark and of course tuning have a profound effect on your experience when twisting the throttle.

    Your biggest issue as I see it is that the problem doesn't occur straight up, but happens after the engine is nice and warm and you're out and about. This will make reproducing it for a mechanic problematic.

    Definitely check the plugs as mike has suggested, but also some questions to think about, because a mechanic is likely to ask ...
    Does the engine sound rough, or maybe like it's "coughing" when it's about to have an "episode"?
    How does it sound when it's idling?
    When it "spits", does it feel like it hesitates a bit before it does?
    Does it lack power at any point (before, during and after a "spitting" episode)?
    Does it feel like you've gently squeezed the breaks when powering through the rev range (I know my old one used to have a "moment" at 7000 when it was due for a service)?

    If anything else occurs to me I'll post it.

    PS. on a side note; my old '88 CBR250-R has just had it's engine swapped after doing the big-end, except the new engine has come with a little quirk ... the new one doesn't fire cylinder #3 until it's warm. You can quite literally hold the pipe out of #3 after starting the engine, and you know the engine's warm when the pipe starts to warm up. Until then, it's stone cold. Love the quirky 250s ;)
  5. Missing can be electrical, I have seen temperature related issues like this when the coils heat up if they have a fine crack in them. The High voltage leaks out and to the frame of the bike. You can sometimes see this in a darkened area. Also spark leads can break down over time and be worse when hot. A couple of possibilities.
  6. thank you everyone for your comments and recommendations as to what this problem might be. I am going to take the bike apart this weekend and replace the spark leads and spark plugs and just give it a general maintenance day with an oil change and such.

    I really appreciate everyones help! i have taken it all into account and i am going to inspect all of the suggestions and change them out regardless to see if thise solves the issues.

    thanks and regards,
  7. ^^ Clean the carbs as well whilst you are there.

    p.s. If you aren't already on http://cbr250.com then join as you will get a tonne of help and info and somebody can probably diagnose the problem straight away :)