Topic: What is involved with new valves?

[ntm1974]

Bike: 74 CB350F

I check all my valves for leakage with kerosene and sure enough, every single one was leaking.  To fix the problem, I figured I could just lap them a little and be good to go.  2 intake valves will not seal in spite of lapping a few times.  I could keep lapping but I am concerned about taking too much material off the head. 

Should I get new valves or keep lapping?  If I picked up two new valves, what else needs to be done?

Thanks for any advice.

[dave500]

post some photos of the work so far.

[ntm1974]

I wish I could but I have the digital camera at work. 

Update incase someone else has this issue:

I doubled down and went from the NAPA abrasive down to a 600 grit abrasive and got the last two valves to hold kerosene for over 5 minutes (I stopped at 5, it may have gone longer.)  Ironically, the valve that took the longest was on the "bad cylinder" that showed low compression and prompted the whole engine tear down in the first place.  I guess in hindsight, I should have tested the valves before tearing into the cylinder head.