Question on lapping valves

[HP HUNTER]

Originally Posted by Jeff Stout

This is on a Harley. I ported a set of heads ( getting ready for stock eliminator LOL). Replaced the valve guides and reamed to .002 to .003 stem clearance. Using old valves and cut face to 45 degree with a 30 degree under cut. Went to head with a kwik way and cut seat to 33-45-65 degree. Lapped valve and checked with flashlight through port and can see light past seat and valve face. Without valve spring and just the weight of valve. After about 4 attempts I no longer see light passing through. I faced new stones a couple times to make sure they were correct. Valve isn't bent. I don't have a way to check seat to guide but guides have a lip and bottom out in head properly I believe. I guess my question is do you need to lap along time to get a 100% seal around seat and valve face? I know its not a class motor but you guys give good honest help. Thanks Jeff

The guide has to be round and strait, that means reaming it undersize then honing it to size, then your seat can be gound or cut and should come in. When you drop the valve on the seat you tap the center of the valve head with your index finger, if you feel any movement its not right.