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idling problem.... help please

Discussion in 'Technical and Troubleshooting Torque' started by junny22, Dec 27, 2005.

  1. ok... left the keys in my cbr and the ignition on all night last week :?
    bugger, flat battery. no worries i thought, just plug the battery charger on and leave it on overnight, right?
    so now the battery shows full charge and the bike will start but now it just wont't idle. it starts up normally and i rev it a bit but once the throttle comes off the bike turns off.
    im sure this topic has been posted before but just wanted to know if anyone has any advice?


    P.S merry christmas people :grin:
  2. Can think of a couple of simple reasons why the bike might not idle (fouled plugs, someones been messing with the idle speed) but can't think of any that would be linked to flattening the battery. You could always try taking it for a quick spin and seeing if getting the engine up to temp solves the problem.
  3. i wasnt sure if they were related but thought it was just a coincidence that this happened after the battery went flat.
    i've gotten the bike up to temp and the bike does go but once the throttle comes off it refuses to idle
  4. Have you tried adjusting the idle speed up a bit?
  5. You may have cooked a coil(s) or another component of the ignition.

    Has been known to happen that the constant current flowing through the coils (as opposed to the "pulsing" currenty in an operating ignition) bi\urns them.

    Get yourself a multimeter and the specs from the manual, and check the resistance of the primary and secondary coils.

  6. How much do the revs drop off when the throttle is closed? If its only dropping off to the normal idle speed then dying it suggests the problem lies with a lack of fuel, air or spark in 1 or more cylinders. If the revs simply drop too far then the idle speed is set wrong.
  7. I'd be inclined to say coils too :(
  8. Check you voltage regulator too, your battery may have got a 'surface' charge but if the regulator is not pumping a nice fat 14 volts into it, you're going to have difficulty keeping it running..
  9. I'm having a similar problem to this with my KLX 250. It only happens every now and then.

    I will pull up to the intersection pull in clutch. And as i come to a stop the engine will stall. Real pain in the butt considering its a kick start, and after stalling it takes a bit to get going again, almost as if it has flooded.

    I tried to make it do it in a car park just riding around, but it wont do it. Only after long stints at above 70km/h. I don't know if i need to change idle or what. I think i'll change the spark plug and see what happens. But any advice would be appreciated.

    It could also be that i'm subconciously releasing throttle while clutch out or something stupid.
  10. Just a few thoughts... Might be your clutch cable catching - is it routed anywhere near the exhaust headers or head? Since you say it seems like it's flooded, it could mean there's something wrong with the carby(s) - making the mixture too rich. Maybe they need a clean? I'm just guessing here though.

  11. Conny: a few other thoughts (after fixing my bike recently):

    It could be your idle mixture is a bit too rich. Can you generally start the bike easily when cold, without the choke?

    With my bike, I got the occasional stall at idle when it was hot, which led to flooding (and mine is kickstart only too, so i know you pai!n). I've since leaned up the idle mixture which seems to have helped. Once the engine is warm it idles no problems whatsoever. but it does now stutter a bit until the engine has warmed up unless i use the choke.

    It should be fairly easy to find the idle mixture screw on the carbie - just note down how much you adjust it by (half turn, 1 turn clockwise / anticlockwise etc) so you can set it back to normal if you make a mistake!

  12. that sounds like what my bike is doin cuvy.
    i finally sent my bike off to the mechanics after a changing the spark plugs and adjusting the idle and still having no luck, the thing will start up and idle when its cold but once it warms up the performance drops off and it won't idle.
    a week later this is what he's telling me he's had the head off and reconditioned, new head gasket, cleaned the carby out, re set and adjusted the valves (which he said was the problem) but the same thing is still happening and theres nothing he can do.
    he recommends gettin reconditioned carby coz its also still running very rich.
    im assuming he would've adjusted the idle/ mixture screw like u said but im not sure. is it difficult to do on a cbr250rr? i've had enough and just want my bloody bike back.
  13. A lot of people don't wait for a motor to heat up properly before tuning the idle mix. Therefore it ends up being rich when hot which will cause flooding and stalling. I sometimes forget to move my choke off the intermediate position and it stalls as soon as I let it idle. ( And no it is not because I am getting senile) Lots do it.

    Because of the time the ig key was on, the coils could be cooked. Also as Hornett says, the battery may have a problem but usually that will show as not being able to re-start. Flat batt syndrome.

    I would start the bike, ride or whatever to get it hot, then tune the idle mix. Step up the speed a little if you need. Then if still plays up, look at the coils.

    Just my opinion.
  14. Well i found my problem.

    There is crap in the carb. I can start mine, and it will idle and i leave it to warm up. But you can hear the idle change without any input. So i got a torch and had a look in the fuel tank. And there is a bit of crap in it. No rust, just junk.

    So it looks like carb clean, and tank flush will do the trick. It will be a fun weekend :)
  15. Sorry to post on this thread after its untouched for a while...

    But, i found a bike which I am considering purchasing (CBR250RR) and it has an identical problem to what Junny22 mentioned.

    The bike idles for a minute (warm), then it just cuts out.

    Junny22: did you manage to solve this problem?

    Anyone else have any suggestions as to what it may be?

    Should I avoid this bike?
  16. It could be quite a number of things. Most of which are carbie related.

    I'd buy it, provided everything else is good, but I'm pretty handy with a spanner. Make sure it has good compression and the bearings aren't knocking.

    Also use it as a haggle point. Chances are that if it hasn't been fixed by the current owner, he/she doesn't know what it is. Play on that, but be aware that bike parts cost around twice what car parts cost and that labour is always more expensive then people expect.