whhen to adjust valves on 3F (1 Viewer)

[VajaFJ70]

3F engine works fine, valves are working smooth and nice but...

is there any instruction (250000, 500000 km or time) to adjust them or just wait till they start rattling??????????

 

[1tontoy]

10K-12K mile intervals...

 

[crushers]

check them once a year...

 

[Hulsty]

WHen running on LPG mine used to start to backfire, meant it was time to adjust the valves! Its due for them again, so thats twice in ~60,000km