Hello Steve!
Bingo!! After reading your comment, I spent some time in front of the TI4 just thinking what could be wrong, then I checked how free it was spinning manually turning the flywheel.
Steve, you were right!!!
I found that on TDC it was loose however on the position the piston was sliding on the liner, it was really tight. Without thinking too much, I removed the spark plug and put a couple of oil drops thru the spark plug hole and turned the flywheel by hand then with the Dremel.
My conclusion was that the oil on the crankcase was not reaching the piston skirt so, I added more oil to it (almost doubled the volume) and span the flywheel with the Dremel again.
It ran a lot more loose. And the result you can see on the videos bellow.
After a little more fine tunning on the carburetor. Better response to throttle
Thank you Steve. Getting advises from experienced people makes a difference
I also observed that if the TI4 gets to hot, it starts getting stuck again, my understanding is that the piston expands different than the liners and cause that situation. The temperature of the water on the can was about 80 degrees C 176F
Well, it is time to start the Radiator and check if it runs cooler.
Edi