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Dear bike doctors: cbr250rr issues

Discussion in 'Technical and Troubleshooting Torque' started by hitokiri21, May 28, 2008.

  1. Gday all,

    Im having trouble starting the cbr, and i'd like to get some input on whats going wrong with the darn thing.
    The bike's been sitting for about 1.5 months, and when i tried starting it last week she didnt want to comply...the starter motor cranked but no joy in starting. Recharging the battery overnight didnt do the trick either. This by itself was nothing new, as ive had issues with the battery being flat frequently (probably a rectifier issue). However when i tried to clutch start the bike all it did was lock the rear brake- clutch starting didnt work o_O

    Prior to this although ive had flat battery problems clutch starting always worked. Ive replaced the battery today and tried again - the starter motor cranking sounded definitely stronger - but again only the occasional burble u get just before the engine starts but thats about it.

    From searching up forums here and there a possible diagnosis is that the top end has seized......which sounds bad :shock:

    Otherwise my next step sounds like i have to replace the spark plugs (which sounds like a bi*ch on the cbr250rr) and check/clean the carbs which with my limited mechanical skills i would prefer not to do.

    Now I've checked the fuel tap position, kill switch position, full tank of fuel, 18 000 km service done at lloyd penn recently.

    If the more mechanically talented ones can give me some direction on with this it'll be much obliged. - thanks fellas
  2. Give Lloyd a call and run it past him.

    I recently had to replace a battery and rec/reg. If the rec/reg is stuffed, it will take the battery with it.
  3. well seeing as it is turning over id say the topend hasnt seized since the cams run off gears

    1)yes it is a pain but check ur plugs.

    2)check ur fuel lines to make sure there flow freely seeing as 250rr dont have a fuelpump.

    3)inspect and clean ur carbs aswell as the manafold for cracks.

    if all the above seems fine try some "startYabasturd" or another aerostart product. if that doesnt work have ur ignition looked at
  4. All the best ;-)

    Trevor G
  5. Step one - get rid of the 1.5 month old fuel and put some fresh stuff in.
    Then follow the advice listed above.
  6. Thanks for the replies

    Another few questions

    1) Where can i find the spark plug socket for the cbr250? from the service manual it says 10mm but the smallest im seeing around on ebay are 16mm
    2) Where is + how can I access the carb bowl drain screw? Im looking at the service manual atm but I cant find any reference to it
    3) Replacing the fuel...is there a tap somewhere in the tank i can use to drain it out? or do i have to siphon it?

    Cheers for the help fellas
  7. 1)The socket won't be 10mm. That would be the thread size. Someone here may be able to help with the true socket size.
    2) the bowl drain screws are at the lowest point of each carbie.
    3) you can drain your tank by putting the tap to "pri" and disconnecting one of the fuel hoses or through one of the carbie drains (thought that will be slower)

    In fact what I would be doing before all of the above would be getting the battery really well charged, putting the tap on "pri" (leave for a few minutes), no choke, then crank whilst gradually opening the throttle.

    Most times a bike will fire like that.
  8. Put fuel tap on prime for a few minutes, come back and start engine with full choke.

    Regards, Andrew.
  9. With the 18,000km service is it an import?might need its 118,000 service!!!
  10. I don't think the average small Honda fuel tap has a PRI position.

    All the best

    Trevor G
  11. If it does have a prime, turn it on. Full choke, no throttle and press the starter button for 5 secs, pause, another 5, then repeat.

    Used to take a while to get the GS started in the cold, seems to start instantly now that I start with it on prime. :roll:

    Any large hills nearby? :)
  12. when in doubt, hook it up to car battery with jumper leads and crank the fcuk out of it. might burn your starter motor out if you crank it for two hours, but thats how i start all my old "sitters".
  13. Thanks for the replies fellas;

    Yeh the cbr250 doesnt have a PRI position on the fuel tap as far as i know.
    Its still a little chilly this morning so I'll wait for the day to warm up a little before giving the bike another go.

    I'll keep u guys updated :cool:
  14. spark plug socket is 16mm for the cbr

    check the negative pressure line is plugged into your fuel tap ... have a look and let us know hoe many lines are running off the tap. Bike will not pump fuel through without neg pressure.

    also did you put the right battery in your bike what type is it? CBR 250's are notorious for battery issues. I'd avoid jumping it off a car as the two batterys are quite different in terms of amperage so you may end up stuffing your new battery. Bike battery small - car battery big - too many amps for bike battery to handle sometimes.

    If it's been sitting for nearly 2 months was the fuel tap on prime all this time? If so your carbs may have filled with old fuel and sludge and your plugs may be saturated with old fuel hence you may need new plugs.
  15. I had the exact same problem on my old CBR250rr, turns out the choke was stuck on because the cable had seized. a bit of wd40 fixed it. you won't be able to tell without taking the tank off and having a look at the choke cable though. does it sound like it wants to start and backfires sometimes when you're starting it?