It's time to replace the seals and I would like to take the easy way out with minimal engine disturbance. There was a tech article but it's link does not work. Here are my thoughts. Remove the spark plug and fill the cylinder with rope. Bring up the piston until it stops (obviously). Compress the spring, remove the clip and expose the valve stem. Replace the seal (this is what I do not know how to do). Reverse process to get back to the beginning. Help with replacing the seal. What is required here.
Thanks,

 

If it is the umbrella style seal just pull them off. there maybe a little plastic install sleeve, that goes on the end off the valve to help install the new umbrella seal. If your new valve seals does not come with the plastic sleeve, then just put a little oil on the valve ead to aid in installing the valve seal. Eric

 

Make VERY VERY sure you are bringing the piston up on the COMPRESSION stroke, otherwise you will bend or break valves and all sorts of other trouble will ensue.
If you use rope, it works best to use soft cotton rope, rather than poly.
If you have an air compressor, there is another way.
Most compression gauges come with a 2 piece hose, with a standard air hose disconnect to allow you to screw the spark plug end in first, after which you attach the gauge.
Screw this lower disconnect into the cylinder you wish to change the valves, and attach an air hose with compressed air.
The compression in the cylinder will keep the valves up.

The RARE event that the air compression won't keep the valve up indicates a burnt, bent or warped valve condition. Which further means you need to do more work than just changing seals.
Hope this helps!

 

When I did mine I had to tap on top and around the spring to get the keepers to let go. I used compressed air and the valve just kept going down. A light tap and then the valve would stay and the spring would compress.