2007 crf 250r all stock impossible to kick start cold, runs and starts great when hot

[mackan_83]

hello.. i live in north of sweden on an elevation of 450m (1500ft) the temperature is about 5-15 (40-60 fahrenheit) celcius now and 15-25 (40-75 fahrenheit) celcius in the middle of the summer and low humidity.

my bike is 2007 crf 250r all stock on it, it has about 35 hours total on it and the piston was changed for not even 5 hours ago and the valves was also adjusted that time. runs great all the time but has been getting harder to start the last two times out on the track when cold.

it started with it starting up easy cold and then it died after a few seconds, and now the last time i was out it was impossible to kick start cold, had to push start it, and when its hot it runs reat and easy to start even when stalled..

the guy i bought it from lived at about zero elevation over the sea and its a bit warmer all year there to and more humid., so its maybe set up for that condition.

what should i do to get it to start cold again?

im checking the valves soon but i dont think its there the problem is.

it feels like its getting flooded how ever i try to start it.. i tried all kinds of tricks to start it that i fund here on tt but nothing helps,

when i kick it slowly to maxium compression when the kick gets a bit stiffer and give a real heavy kick i get a bang in the exhaust but no indication of it starting..?

i seen a lot of posts on here about this but no complete solution thats sure to work,, please help me get this beast started so i can ride the short bit of season thats left here, only a month before it starts snowing:crazy:

[Wayward Son]

check valve clearacne and cam timing.

[sneakysneaky]

My crf250x has the same problem! It has a brand new 07r RHC head on it and a hi-comp piston, the engine is perfect, EXCEPT for when the outside temp is below 10 degrees C in the morning and the thing just wont start, although it is a good warm up in cold weather. my solution was to richen it up for winter, i've gone from a 42 to a 45 pilot, and a 168 main jet, havnt touched the needle as it runs good when started. but you definately need at least the pilot richer in colder months. i crank the throttle twice then it usually fires, if it stalls i twist it once again and try again till its running. I am at sea level but this hasa pretty well fixed my bike. hope this helps!! good luck!!