I think Kawi reccomends adjusting every 150 hours

 

The FX850 is a 27 hp engine. It always was, but used to be rated under a system that was very flawed and was rated at 31.

Regardless, Kaw recommends adjusting the valves every 300 hours.

 

That first valve adjustment is the most important if things wore in so theres no valve lash left. Now the valve isn't completely closing. After that they usually are loose and making noise.

 

Always found my v-twin Kaws so much quieter/smooth-running after adjusting the valves.

On my current and new-to-me commercial Honda GXV390 pull-start engines, the first valve adjustments contributed to easier starting. When new a short 1/3 pull and they'd fire right up...but after several hundred hours it took a deeper, near full pull. Valve adjustment and right back to the short 1/3 pull.

 

As posted, the first is important.
I’ve never seen the lash tighten unless theres a guide problem.
After the first, they seem to hold for 1000 hrs.
Good rule is when they tap and have that metallic tick, do them.
Only problem is its a slow process of the sound and you may
never notice.

If you let them go, it could get very expensive.

 

On our maintenance logs we like to check valves twice a year, once in the summer and at the end of year. Just to be safe.