Hello, the explanation is a bit long, although you can search the internet "regulate 3-cylinder motor valves"
1-Sacar valve cover.
2-Piston 1 (the one that is closer to fan blade) at the crossroads of valve or the precise moment in which it finishes closing an escape valve and begins to open the admission, this is called "valve crossing".
3-Chark with chalk the steering wheel and housing when the valve is achieved at crossing and then turn a complete turn the engine so that the pulley is where, at that precise moment those valves of that cylinder will be ready to be regulated (I ignore the valve strike of the Kubota).
4- Once regulated cylinder 1, delete the aid marks made with chalk and re-carry out the maneuver from zero applying this operational range from point 2 with the cylinder that follows or No. 2 and repeat with the 3 and close
I have no photos to support with illustrations