250F Problem with idle and oil out of breather hose

Hi guys! I am new here, I am from Romania.

I recently bought a used Kx250f 2011(injected) and making a long story short i did not tested the bike because it was a rainy day, only started the bike and let it idle and rev a couple of times (i had no experience with bikes). When i took the bike for a ride, after 2km the bike would not keep an idle, it stalled and died if not keeping it accelerated from the throttle.

In short i ended up rebuilding the head with new titanium valves and seat cut at specialised service. This did not solved the issue, the bike still will not idle.

After watching some videos on youtube i have seen a guy having the same problem because of the ignition coil. New ignition coil added and the problem is somewhat better, it wont keep an idle when cold but when hot is idling, only if the idle screw is at the max left (max rpm)

I did self diagnose and found a faulty connection to throttle sensor. Fixed with a new connector, no more error codes. This did not fix the problem.

Cleaned and checked the injectors with carb cleaner, injector jets look good. This did not solve the problem.

I took it for a ride after all this and it is not working right, it is stalling and when i press the clutch the engine revs very hight at idle (might be because the srew is at max or a stuck injector).

Also it is leaking oil from the breather hose after a ride, only after you ride it.

The timing is good, checked, the valve clearance is good, checked.

Please guys, help me, i am out of ideas and out of money.
 
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Hi guys! I am new here, I am from Romania.

I recently bought a used Kx250f 2011(injected) and making a long story short i did not tested the bike because it was a rainy day, only started the bike and let it idle and rev a couple of times (i had no experience with bikes). When i took the bike for a ride, after 2km the bike would not keep an idle, it stalled and died if not keeping it accelerated from the throttle.

In short i ended up rebuilding the head with new titanium valves and seat cut at specialised service. This did not solved the issue, the bike still will not idle.

After watching some videos on youtube i have seen a guy having the same problem because of the ignition coil. New ignition coil added and the problem is somewhat better, it wont keep an idle when cold but when hot is idling, only if the idle screw is at the max left (max rpm)

I did self diagnose and found a faulty connection to throttle sensor. Fixed with a new connector, no more error codes. This did not fix the problem.

Cleaned and checked the injectors with carb cleaner, injector jets look good. This did not solve the problem.

I took it for a ride after all this and it is not working right, it is stalling and when i press the clutch the engine revs very hight at idle (might be because the srew is at max or a stuck injector).

Also it is leaking oil from the breather hose after a ride, only after you ride it.

The timing is good, checked, the valve clearance is good, checked.

Please guys, help me, i am out of ideas and out of money.
You may have gotten close to the fix. I’d look at the tps again. If that sensor has an open spot, which quite often is just off idle, it could cause all your problems. This could be checked by using an ohm meter to check resistance on the unplugged sensor, not sure what the range is but it should have a steady increase and decrease in resistance on a slow throttle sweep with no drop outs. If there is a drop out, replace the tp sensor.
 
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You may have gotten close to the fix. I’d look at the tps again. If that sensor has an open spot, which quite often is just off idle, it could cause all your problems. This could be checked by using an ohm meter to check resistance on the unplugged sensor, not sure what the range is but it should have a steady increase and decrease in resistance on a slow throttle sweep with no drop outs. If there is a drop out, replace the top sensor.
Thanks! I will check that
 
Do you think the cam lobs are ok?
 

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The TPS is ok, i checked it now and has no "dead spots". Should that black thing that comes over the spark plug have in internal resistance, like 5K Ohms? I suspect that is something wrong with the intake cam, it is a bit upper than the exhaust cam even though the timing is spot on.
 
The TPS is ok, i checked it now and has no "dead spots". Should that black thing that comes over the spark plug have in internal resistance, like 5K Ohms? I suspect that is something wrong with the intake cam, it is a bit upper than the exhaust cam even though the timing is spot on.
The ignition wire should have a resistance of around 12k ohms per foot. The cams look ok most likely, the intake valves and exhaust valves open 20 degrees short of one full crank revolution of each other, and those lobes look like they correspond with that. Only way to be sure would to get a degree wheel, and a dial indicator to check proper valve opening.
 
Nothing wrong with ignition, checked it very well, the coil is new, spark plug is new. It is a weird, weird fault. The diagnose light stays off, so there are no errors.
 
The ignition wire should have a resistance of around 12k ohms per foot. The cams look ok most likely, the intake valves and exhaust valves open 20 degrees short of one full crank revolution of each other, and those lobes look like they correspond with that. Only way to be sure would to get a degree wheel, and a dial indicator to check proper valve opening.
Thanks for the reply, Steve. I really appreciate it
 
Now i am starting to think it is a fuelling problem, i can keep it running if i spray carb cleaner on the filter.
What do you guys think? I have no device to measure the fuel pressure right now so it is only a guess.
 
Now i am starting to think it is a fuelling problem, i can keep it running if i spray carb cleaner on the filter.
What do you guys think? I have no device to measure the fuel pressure right now so it is only a guess.
Check for air leaks, try spraying carb cleaner around the intake.
 
Check for air leaks, try spraying carb cleaner around the intake.
Steve, do you recommend me a 2 smoker? :)))) It would make my life so much easier :))) Unfortunately i am stuck with this one, i have to fix it because i can't sell it like this broken. Or maybe if i like it after i fix it i will keep it, don't know, i'll see... Right now it makes me go mad :)))
 
Steve, do you recommend me a 2 smoker? :)))) It would make my life so much easier :))) Unfortunately i am stuck with this one, i have to fix it because i can't sell it like this broken. Or maybe if i like it after i fix it i will keep it, don't know, i'll see... Right now it makes me go mad :)))
2strokes are simple, and fun to ride. My advice is to ride what you want, there’s a lot of choices out there….but there really isn’t a bad dirtbike out there in the modern era.
 
When i start the bike cold the fuel pressure at idle is 43 psi but after i rev the bike and gets hot is settles at aprox. 47 psi, at idle, is this normal?
 

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