2010 Te250 Engine Won't Stay Running

I have been given a bike that wasn't running in hopes I could make her run.
The TE250 will start and run for a short time, once the bike is hot, it will stall at a stop, start again but as soon as I tough the throttle it dies.

I had the engine rebuild, New piston and rings, new valve springs. Running the upgraded exhaust, with the O2 sensor bypassed with the jumper plug.The air filter was replaced and the plastic restriction piece has been removed.

Originally there was a problem with the exhaust spring being too loose, which would allow the valve to slightly open and loose all compression. When we ordered a replacement spring it also came with a low amount of spring pressure, had to get a second one shipped from the manufacture. (they mentioned they were having problems with this issue). Ok, so now the bike mechanically should be good to go.

I am wondering if I am getting enough back pressure with the exhaust pipe, and if I should put the spark arrestor back in (would have to be modified to fit).

I have the iBeats program, but not sure what settings I should be looking for. I can get the bike to start, but won't stay running.

Any advice or help.
Thank you for all your help

My 2010 TE250 just did the same thing.

Where are you located?

My thoughts are:

Bad coolant temp sensor
or
Bad fuel pump

I-beat without the S/A in the pipe
Co1 105
Co2 109
co3 107

TPS 102.3 @ WOT warm engine. (or about .977mv)

iBeat will give you the temp sensor reading so you can check that easily. When the bike is cold the temperature should be the same as ambient.
Sounds like a fuel pump issue or blocked fuel filter.

Hey, have you been able to sort the issue out? I’m currently in the same boat as you. New engine, fuel pump, spark plug, cleaned injector, lots of spark, valve timing is good, ignition timing is good. Diagnostic tool says open injector circuit but having a hard time tracking exactly what it is.

Open injector circuit means the ECU can't "see" the resistance of the injector. Check the injector connector is seated properly and that the injector-to-ECU wiring is not chaffed or shorting out.

Also, use a multimeter to check the injector has some resistance and is not open circuit. Faulty injectors are very rare but it's possible.

Update, my apologies for not checking in sooner. found out it was the stator causing all the grief, apparently. new stator from a SHERCO, and no more issues. I can't see the logic in how a bad stator, but a fully charged battery, would cause it to run like shit, but problem is resolved. I've been running now for a couple of weeks with no issues anymore.

That's a good result. Thanks for letting us know.

We need pictures and part numbers please. This is the first I've heard that a Sherco stator works. Details!

your problem is/was probably the pick-up coil; which is part of the stator assembly.

So I have my old stator, but the shop told me they used a SHERCO stator but had to swap the plug on the pick up coil. I’m not sure of the part number but I can try and find out that info, I did look at my paperwork for numbers, to no luck. Also, do you know anyone that rebuilds stators?

Closer to you than to me (New Hampshire):
https://ricksmotorsportelectrics.com/

They have a core charge, so they're really not rebuilding/rewinding yours.

Ricky Stator is a different California company (and the most famous). I thought the founder died but it seems to still be going:
http://www.rickystator.com/

Take pictures of your new and old stuff for us... and future readers.