09 Kx250f Problems i can't figure out

Hello. I bought an 09 kx250f this winter. first rides went great. but just before my first race, the bike wont start. it popstarts but will not kickstart. After the bike is popstarted, it runs just like it usually does. Ive changed the spark plug and cleaned the air filter. CAN SOMEONE PLEASE HELP ME WITH THIS ISSUUE?!

Sounds like valves to me. Im gonna take a swing in the dark and say one of your intakes are out of spec.

Yup, classic symptoms of needing the valves adjusted.

Engine cold.. Intake.. 0.10~0.15 mm.. Exhaust.. 0.17~0.22 mm.

If it could possibly be that, can it still be raced with until i have the time to get it fixed?

If it could possibly be that, can it still be raced with until i have the time to get it fixed?

Not a good idea. The longer you run it with them leaking, the greater the chance a simple valve shim job will turn into a total head rebuild.

oK but i dont see anything leaking? im new to having to adjust these things

And if once the valves are shimmed, do i have to rebreak in the bike or can i just go ride?

And if once the valves are shimmed, do i have to rebreak in the bike or can i just go ride?

Shim and ride.

ok thanks everyone

how will i know if there is damage to the valves and the head when i shime them?

you wont...... u can take the valves out and inspect the valve where it meets the valve seat. If it looks like it is starting to tulop then ur going to need valves or you can reshim and if your valves zero out with in 5 hours then your valves are done and should not be ran as u are at high risk of droping the valve. what hapens is when the valve comes up and meets the seat, the seat materal is hard and wears into the valve where your valve meets the seat at an angle. once the valve coating starts to wear then then it will continue to wear until the valve will be beaten into the seat so much that the keepers up ontop of the spring will come off and your valve will drop into the cylinder and meet the piston and boom motor is done.

OK thanks at least that hasn't happened yet lol.

Once you shim the valves, you must begin to make plans to have then replaced. To wait is an invitation to a catastrophic engine breakdown. This means if you reshim, in less then ten runtime hours, get them done. Pay a little now or a lot later.

As I posted in another thread, I had this exact issue on my 09 and it was a bad coil. Started cold first kick, but would NOT start hot. I checked my valves a hundred times. lol

As I posted in another thread, I had this exact issue on my 09 and it was a bad coil. Started cold first kick, but would NOT start hot. I checked my valves a hundred times. lol

not his problem...... his bike will start cold but by bump starting it and then once its warm start fine its opp, I agree if the bike starts cole but then when it gets hot dies or doesn't start then its most likely the stator or coil - useually stator....

his explaination of not starting cold other then bump starting untill it has fired for the first time that day and warm is useually intake valves being tight.

Aah, there's a million of these threads, I guess I didn't read it read it carefully enough! sorry.

No the problem with it is it wont kickstart at all it has to be popstarted

No the problem with it is it wont kickstart at all it has to be popstarted

even once the bike is warm and has been running it still wont kick start?

no has to be popstarted

the only difference between bumpstarting and kicking is obviously with bump starting it is going to have more rotations and faster then kicking. I would check valves and if in spec clean the carb - and check stator and coil for ohm readings

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