Motorcycle Repair: 86 XR600 Woes - Please Help!, intake ports, combustion chamber

Question
A couple last questions if I can-
Is it necessary to lap the new valve(s) with valve grinding compound?
Any tips on installing the new one(s)?

Thanks once more for your expert advice,
Chris

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Followup To
Answer -
Once the head is off, with cams out and valves closed, just spray some carb cleaner down the intake ports with the head set up on edge, so you can fill the ports with an inch of fluid.
Watch the combustion chamber and you will see pretty easily where the leak is. Repeat for the exhaust side to confirm.
You can take the valves out, put them in a drill motor and spin them. Bent ones are pretty evident..

Bill

Answer
Definitely take some fine lapping compound and lap each one in, so you can see a nice clean seat surface on both the valve head and the valve seat. You will see a fine gray line on both. If you don't have a lapping tool, you can rig up something with a slow speed drill motor and a piece of rubber tubing that will hold the end of the valve stem.
Put a little compound on the valve head, slide it into the guide. Place rubber tubing into the drill chuck and slip it onto the valve stem tip. Run drill motor slowly and pull valve into the seat for a few seconds, release, and pull in again for a few cycles. If everything is in tolerance, you should see a seating ring form fairly quickly.

Bill Silver