jamesfoster Posted February 25, 2014 Share Posted February 25, 2014 Hi all, sorry to raise conundrum on my first post, but this is driving me mad, so hope anyone can possibly help with an ignition problem on my ybr125 07 plate (carb version) since around november last year my bike has been reluctant to start with a warm engine, eg i've taken it out for a run, stopped, and couple of minutes later when i'm ready to go again, my bike doesn't want to start. it will start fine from a cold engine on or off the choke, and once it is running (hot or cold) it runs fine and you wouldn't suspect a thing. i did suspect it might be the coil breaking down but the replacement hasn't seemed to make a lot of difference as it still is playing up.... so far i've replaced/serviced/cleaned the following: cleaned air filter, replaced coil & ht lead, replaced plug cap, new spark, carb cleaned, seal replaced on inlet manifold where it was blowing. the spark colour is fine and the mixture isn't too lean/rich etc one consideration - before i took the bike on last June, it had been garaged for about a year with an almost empty tank, and i suppose there is a possibility that some gunk might have accumulated in the tank - but like i said, when its running you wouldn't notice anything was ever wrong with it. one last thing i'm yet to do is put some Redex through it when i fill up next. any ideas? it is driving me a bit mad, and making me really have to think hard about distance from home vs engine temperature when i go to fill up. I posted elsewhere and 2 suggestions were to check the choke seating, or that it could be the float...but when we gave the carb a clean out both seemed fine (although i'm no expert...) please help! cheers James Link to comment Share on other sites More sharing options...
dt502001 Posted February 25, 2014 Share Posted February 25, 2014 CDI's can act that way,any back fire or poping when it wont start? Link to comment Share on other sites More sharing options...
dt502001 Posted February 25, 2014 Share Posted February 25, 2014 Another thing to try is heat up the pick up coil with a hair drier and see if it starts cold,and check the resistance hot vs cold with a dvom Link to comment Share on other sites More sharing options...
jamesfoster Posted February 27, 2014 Author Share Posted February 27, 2014 CDI's can act that way,any back fire or poping when it wont start? hi dt502001 - when its being fickle there is the very occaisional pop or half-hearted backfire, but normally no unusual noises at all, almost feels as if its turning over without fuel flowing, but that's cobblers because the fuel is clearly flowing free on the days that it starts 1st go,and once its running its as smooth as you'd like. to be honest if it hasn't started after about 5 seconds i give it 2 mins grace to get over itself, then if it still doesn't want to play nicely i revert to my classic fix which tends to be remove spark, turn it over for 1 - 1&1/2 seconds, replace everything, and it starts on the first turn of the crank. this means i now constantly have a spark socket in my pocket wherever i go - which isnt exactly perfect... Link to comment Share on other sites More sharing options...
obriens65 Posted February 28, 2014 Share Posted February 28, 2014 CDI's can act that way,any back fire or poping when it wont start? A friends 125 was acting in exactly the same way and it was the CDI on it's way out. Link to comment Share on other sites More sharing options...
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