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CBR250RR not starting, any ideas?

Discussion in 'Technical and Troubleshooting Torque' at netrider.net.au started by uforixx, Jan 31, 2011.

  1. Got my 91 CBR250RR a few weeks ago, and up until recently has been running fine.

    That changed when I put E10 in accidently.

    Lost a heap of power below 8,000 revs and was generally running like a scooter, being dragged off by middle aged mothers in their Corollas....etc.

    Had a poke around and found the cause - fouled spark plug. Changed that and it was running perfectly! - for 3 days.

    Had a few good rides, then on Saturday I rode from Hornsby to the city and back - no problems.

    Get home, in the garage, shower TV etc.

    Few hours later go to head out again, and low and behold it wont start.

    Starter motor runs, headlights strong, indicators fine, engine just wont turn over.

    Was quite low on fuel when I got home however didnt need to switch to reserve. I did put some more fuel in however same outcome.

    It confuses me that it goes from running perfectly with no problem to simply not starting at all a few hours later.

    Oil is between the dipstick indicators also.

    Possibly another spark plug? Carbs?

    Any ideas or suggestions from the more experienced would be greatly appreciated!


  2. The e10 etself wouldn't be the problem. I'd say it's more like the e10 dislodged some gunk in your tank and you have a stuck float needle.

    To start, hold the starter button and slowly wind open the throttle. No choke.

    Give it a good thrashing and that might clean out the carbies otherwise you might have to clean them.
  3. I tried that starting technique yesterday to no avail.

    Im growing more suspicious about the carbs although so might pull them out for a clean.

    Thanks for the reply!
  4. checked the obvious.....kill switch, side stand switch, fuses........
  5. Have tried all but fuses, unsure about them.

    Will give it a go when I get home from work.
  6. It doesn't sound electrical. To confirm, get one of your old plugs, clean it up. put it in a lead and earth it on the side of the engine. Hit the starter motor. Should get a good blue spark (provided it's not too bright outside)
  7. I too vote carburettor related issue.

    E10 fuel (anything with ethanol) should only be used in late model efi engines. Anything old school like your bike will run fine at first but the ethanol can eat away at rubber hoses and seals in carburettors if left in there for several days. In emergency situations its still fine to use as long as its completely flushed through and replaced with regular fuel as soon as possible. Most times it won't do anything but its not worth the risk to use regularly.

    Unless you see fuel dribbling all down the side of the engine I doubt its anything serious, but could be as little as a hole worn through on a manifold seal allowing more air in and creating a mixture so lean it doesn't fire.

    Ibast's idea of the E10 dislodging previous build up of crap is very likely too and unless you can get it started with lots of fiddling and start ya bastard sprayed in every orifice you can find around the carbies then I'd say it needs a manual cleanout.

    It isn't a difficult procedure to clean the carbs, but rather time consuming (expect an entire afternoon at least). There should be a service manual for your bike that explains step by step how the carbies are removed and disassembled, clean them out with a can of carby cleaner + toothbrush/rag til its all nice and new then reassemble exactly how it came apart.
    It'd be worth getting a knowledgeable friend to help out just to speed things up, especially if they can bring their own tools and beer.

    Good luck gettin 'er going again (y)