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CBRR 250 not accelerating

Discussion in 'Technical and Troubleshooting Torque' started by leviathan, Feb 24, 2007.

  1. Hi,

    I have a 1991 CBRR 250.

    Recently I have started noticing a flat spot around the 8k rev mark when giving it horns this has only just started to happen in about two weeks of riding once a weekend.

    Just yesterday I went for a ride and all seemed ok and went ok.

    Today I went for another ride and was giving it a bit. In third gear I heard a whistling noise so I backed off and changed up.

    I was getting a pretty pungent burning smell and worse of all when I give it a about a 1/4 bit of throttle it doesnt really go and makes GRRR sound like something is misfiring. If I just trundle along it seems to be ok but still very flat better in 1st, 2nd.

    Also I filled her up with BP 98 for the first time yesterday as opposed to 91 as I have heard this can clean things up inside the engine.

    Is this anything I can fix (Basic/medium tech skills) or check or should I take it to a bike mechanic first off... and if so can anyone recommend someone in the city/Albert park region... in Melbourne.

    Added..: The idling either hot or cold is slightly rough. not sure if it is related. There is also a high pitched ticking sound, I am thinking the tappets and the carby need a clean ?

    Thanks !
  2. doesnt sound like a major problem. i have been through these problems before.
    defintely check your air filter. sounds like its dirty or blocked somewhere.
    if that doesnt work, then sounds like your carbs need tuning. after that your bike should be ok
  3. If missfiring, i would be looking at your spark plugs or leads, as they can often be the culprit for that. Do you know how long ago your plugs were checked/ changed?
  4. Thanks for the quick replies. I will check all the obvious.

    I am not sure, as I only bought the bike in December. I am going to get it fully serviced ASAP.

    I have heard of someone who repairs bikes out near Bikemart. Can anyone comment on this ?

  5. I

    I used to use the normal unleaded in my hyosung gt250r when i first got it and the started to put vortex 98 in it over last couple of months. I think that someone explained it to me that it is becuase the 98 burns at a higher temp works better at higher revs. So when your in the lower revs it may sound a bit rough.
  6. Nothing like that unfortunately.

    I have tightened up the chain and cleaned a few other bits and pieces. Took it for about a half hour ride and it seems to be a lot better.

    Going to get it serviced anyhow.

    Anyone recommend the place out the back of Bikemart ?

    Thanks !
  7. Out the back of bikemart? You mean A1, or Eastern motorcycle wreckers. (I'm thinking of the right bikemart right)
  8. Mine did the same thing, ended up being a heap of sludge in the carbies
  9. In-tune Auto. I got a friend to look at it.

    Willl let you know what it turns out to be.
  10. Well so far we have found the following...

    The spark plug cable needs to be replaced as it has some nicks in it that have been repaired with sticky tape !!!! The third plug has very high resistance so going to replace that one as well. The plugs are also gone so they need to be replaced.

    Brake fluid is contaminated, replacing.

    Oil needs replacement using mogul mineral stuff.

    Carby's are full of fuel. My friend does not want to do the carbies as he can't balance them. Should I ask him to clean them anyway or is a proper balancing etc neccesary ?

    So far I have been quoted in the range of 150 to 270 for a carby service. I asked about rejetting and most of the people I spoke to told me that a rejet is hardly ever neccesary.

    Does anyone have any experience with brighton kawasaki ?

    I also checked the choke the otherday if you try to use the choke, the bike just dies. Does not want to start. I would think this would point in the direction of the carbys again as there is to much fuel for it to run ? (Keep in mind aftermarket pipe probably without a tune afterwards...)

  11. i had teh same kind of problem witryh my zxr. it all turned out to be a blown offvacume hose
  12. Probably better to replace the oil with at least semi-synthetic oil as the RPM the CBR250 gets up to (19,000 redline) Synthetic is going to be a lot better.
  13. Pity i didn't see this earlier, originally i had a problem like this, my sparkplug was just sitting ontop of the cavity for it :shock: and thats why it was making that huge GRRRRRR on acceleration :shock:

    But if your in the Brighton way take it to A1 brighton, see if you can get a guy named Dylan to look at it, he serviced mine (from his home business however, i'll see if i can get you a card) for almost 2 years and was always great.
    He took care of everything, and it ended up going faster everytime i rode out of there :LOL:
  14. Thanks for the post albeit a bit belated.

    It turns out it was a mixture of fuel problems and spark plugs.

  15. high octane fuel in CBR250

    This may be a bit late but maybe worth considering,

    I was told by 2 seperate shops to never run high octane fuel in my CBR250RR as it will foul the plugs and cause you to slowly lose power.. getting worse and worse..

    maybe this is what caused your plugs to foul up.

    I just thought if this was the case it may prevent it from happening to you again.

    Edit: but i'd check that what im saying is correct for you as your bike may have been tuned for different fuel as yours may be a import model and mine isnt.
  16. Youre carbies are meant to be full of fuel... You wont need a rejet, only if you dramaticall change induction and exhaust. You could put a feul cleaner (flush) mix in with the petrol, such as wynnes or nulon fuel additive. This would be a good idea before and after the service, and periodically. I got 160,000 kms out of the spada without taking it to a mechanic and doing the basic stuff myself, before i killed the bottom end.
  17. Re: high octane fuel in CBR250

    I ALWAYS ran either Mobile 8000 or BP Ultimate in my RR and never had a problem... i did have nichrome plugs tho, dunno if that helped.
  18. Its true about the Premium 98 fuel. FZR250s don't run well on the stuff because their carbys have been adjusted to run on normal Unleaded. Many people on the FZR forums have experienced fueling problems when running premium and having it going away when changing back to ULP.