New user. New (used) '02 GS. Repairing it. Need advice

[ben2go]

Was able to fit the tappet (valve bucket) in another valve after heating it. It now even spins by hand!
I tested the valves again for leaks, but this time pouring acetone in the ports, not in the combustion chamber.
It seeped through both intake valves. No real leak, just seeping enough for me to notice the littlest bit of moisture around parts of the edges of the valves.
Now I'm unsure if this happened because of the penetrating nature of acetone. I'm wondering whether this seepage is enough evidence to justify lapping these valves. I just don't want to do something if it isn't needed (plus I really want to finish putting it all togeher to start the bike and move on to working on the carbs). I'm planning to redo this test with water. I'm suspecting that with water being denser than acetone, it might not seep like the acetone did.
Any opinons?

You should clean and lap the valves while you have the head off.

Here's a vid http://www.youtube.com/watch?v=tZgzrRi_tyw