`11 250f starts then shuts off, any ideas

[motovet]

I am helping a friend with their 2011 kx250f. To tell the story, he put a new piston in it just for basic maintenance, piston, rings, pin, clips and gaskets. When he fired it up it ran good but smoked, so he pulled it apart and found he had the oil ring wrong ( not sure what he had wrong). After getting it back together again he started  it and it ran for about ten seconds and would die, give it a couple seconds and kick it over, same thing run then die.after looking it over again and again, starting it again and again now it wont start and he asks me to help. So, now that I have it here to look at, I know it won`t start, I do have spark, kicking it the compression feels good, did a leakdown test and it is very good, the cams are timed correctly, I have tested the vehicle down switch, gas is getting to the piston ( plug is damp, almost wet), I did the self diagnosis with no codes coming up and i put a different tank on it to try another fuel pump. So now I am out of ideas and started to pull the engine apart. The only thing I notice so far is that the piston has marks from all four valves on top, so at some time during all of this he must have had the timing off some. I checked each valve and they are not bent. I filled the intake part of the head with brake clean and they sealed great, nothing leaked through and did the same on the exhaust side. I also pulled each valve out to be sure they were not sticky. It has a vortex piston and cometic gaskets in it. Any ideas? I am lost on this thing

[Foxx4Beaver]

I don't know Jack about the 4T's...but do they have an oil sensor that keeps it from running if the oil gets too low...does it need oil?

[motovet]

I did not see anything about an oil level sensor in the book, but I did check the oil and it was full. I will look to see if it has one, if it does I can test it to make sure it is working right.

[Foxx4Beaver]

if that's not it, then possibly carb related.

[motovet]

It is fuel injected, I wondered about that with the spark plug being more on the wet side when I kick it over. I don`t see much in the manual about testing them, it talks about power and resistance test but not sure how I would check the spray.

[Foxx4Beaver]

give it some time...there's a few members on here that are really good with the 4T's, but they sometimes don't log-on everyday...
in the mean time, you can scroll through the KX450F/KX250F threads and see if you can come up with some ideas to check.

[motovet]

ok, thank you, also for your input on my 500 yesterday.

[Foxx4Beaver]

you're welcome...just pay it forward

[motovet]

Sooo......... I am not sure if this is what caused this whole ordeal or not but what I found is the gaskets for the cylinder and head did not have oil holes in them ( the ones to allow oil to get to the head). I know they are aftermarket but not sure what brand and he does not remember either, I don`t know if it was a gasket manufacture mistake or if they were for a different year ( would assume all years would have some type of oil hole though). As I look through the manual, I don`t see anything about oil pressures shutting it down but it works fine now and that is all I found to be wrong. Not sure if this will help out anyone else with running issues but it may just save a top end from lack of oil. Moving parts like oil

[Foxx4Beaver]

makes sense, I never thought of the head gasket, but like I mentioned in my 1st post, "I don't know jack about the 4T's"...and plan on keeping it that way

glad you got it sorted out!