Hello. I have a sr50 factory, 40,000km. There was a problem with the water pump, it started all right.

First I took off the injector and replaced the seal under my head.
Then problems with idling and starting began.

Then I built the engine, a new water pump, a new cylinder seal (0.8mm), a new injection seal and head.

Now, if it's cold, it starts well and goes well behind the gas.

After warming up after a few minutes, I must hold the starter for a long time before grabbing. It does not go very fast, runs for 1-2 minutes at idle and goes out.

The pressure of the air pump is 110-120 psi. Some idea? Thanks