My K1 is in the need of a valve job due to a slightly burned exhaust valve.
According to the repair manual (Clymers) the valve is not serviceable and has to be replaced. Is it really so and what is the reason ?

Cheers
JB

The valve doesn't have any extra of material that can be grinded away to have a new perfect sealing of the combustion chamber against the seals placed in the cilinderhead. Apart from that the valve material characteristics have most probably been altered to to the overheating by which eventually the burning took place.