B1200 Valve Adjustment

[MEAKN]

I have an early '90s Kubota B1200, that I've owned for a few years. It's one of the most dependable pieces of equipment I have. Since I don't have a shop manual for it, I've been wondering whether or not the valves need adjusting on a periodic schedule. Does anyone know the specs for valve adjustment (if necessary)and/or have any tips/anything else I should be aware of??? Thanks. I can check back during the day.