my tc 250 review the good, bad and ugly!!

All the other stuff (manifold, wires etc) is still worth checking out.

Seems to be valves seats mayb or bad wotn valves

Maybe some of carburetor needle is clogged, is that hard wotk to clean the pilot and manin jet??
Carburetor must be unmouted before that work or is there some tricky work?

Trenchcoat is probably right about the accelerator pump. A JD jet kit would probably have the correct size of leak jet for it. The duration of the squirt of the pump is also important. Correct would be 1.5 to 2 seconds. Some carbs will pump for 6 seconds which is way to much. There are some videos out there on how to adjust the duration of the squirt.

So i performed testing of motor again, motor starts ok, 1 to max 5 kick when cold, idle works perfectly (sound is good, might be ok), motor run good to about half of throttle opening, slowly, when trying to accelarate with throttle opening faster from about half to full throttle, motor starts hesitate and like in video above there was a sound like electric short circuit

make sure your main jet has not fallen out.

inspect the carburetor thoroughly.

start a new thread.

I can't believe but hesitation and other problems while accelerating is caused by elctrical contact corrosion, maybe becase too much moisture in my garage.
I clean all contact - TPS sensor contacts, stator external connector, spurg plug connector, ignition coul grounding contacts and blowig them with compressed air, motor works fine after that wothout any single problems!
But i did not figured out which contact makes me problems because i cleaned all i mentioned above.
So deffinitelly there is no problem with carburetor or valves because motor works very well.
A assumed there problem is in TPS sensor connector, bad contact or moisture came in contact between two pins and casued different resistance reading for ignition timing.

What is solution for hard start?
Last year i have no problem with starting motor cold or hot but now i cant start motor without pushing it in 2nd gear.
Hot is better especially with hot start button.

I clean a carburetor, i clean air filter, a check electric connection and i have no idea anymore what could get wrong.
When motor start whit pushing it turn off itself after 1 second and i must retry starting with little bit throttle opening and keep open one minute to obtain stalling motor condition.

Valve adjustment I’ve heard. Pretty sue my dealer (George Erl, Uptite) set an intake a little loose.