[Tim Cline]

To add to what straydog said, another way to change valve seals with a piece of rope. I know this sounds weird but I have done this and it works. Here is the way I did it to keep the valves from falling down when keepers are removed. Remove spark plug, rotate engine until cylinder is at TDC (both valves closed),(watch rocker arms) and then Timing mark to confirm TDC. Rotate engine (lower piston) until you can see top of piston thru the spark plug hole. Now here is the trick -you need about 6-8 feet of tightly wound rope maybe 5/16"(just smaller than the spark plug hole). Push all the rope you can fit into the cylinder (fill the cylinder), (leaving enough to pull back out), rotate piston back up as far as you can to compress the rope against the valves. Do this by hand not with the starter. Now your valves will stay in place because the combustion chamber is full of rope and there is no room for them to fall into the cylinder. Remove keepers and replace valve seals and keepers. Rotate piston down until rope is loose and can be removed. This has one more added benifit that when you pull out the rope most of the carbon on top of the piston will come out with the rope. I hope this trick will be useful.