how often

[bracing]

When do you know its time to lap your valves.

[goffin20]

Depends on who you ask, some say as often as you can, others say never.  I leave that up to my builder to decide.

[clouse55]

 Anytime I had to pull the head for tech I always took a good look at the sealing surface of the valves. Most of the time at assemble I would VERY LIGHTLY lap them. The more run time a valve has it "use hardens" and you end up grinding alot in the seat. Probably best to let your builder take care of it during a "freshin up'   

[Swartz]

Take the head off and turn it upside down on a table or something. Pour the thinest fluid you have available, lighter fluid, Kerosene, etc. in the combustion chamber. if any, or much, fluid leaks past the valves into the intake or exhaust port, well, you alredy have the head off. It's usualy best to replace the valve and start fresh.