#4 plug getting oil fouled

Hey all,
So i'm seeing some unusual oil fouling on the #4 plug on my GPz1100 . About 7500 miles ago I had to have the head's valve guides replaced from a siezed exhaust valve guide.  While the engine was disassembled I honed the cylinder and replaced the piston rings. The engine has about 14K total mi currently. This engine has always burned some oil, but never a smoker.  I'm suspecting a bad intake valve seal as when the valve is open, I can actually see a lot of oily crud on the backside of the valve face when looking down into the cylinder. My question is has anyone sucessfully changed out a valve seal not having to remove the cylinder head ? 

It indicates oil leakage to the combustion chamber. The main reason is bad piston rings or excess engine oil. Please replace the piston rings and see whether the problem is fixed or not.

I have read about two methods, but have no personal experience with either of them.
1. Putthe piston a bit below tdc. Thread some small diameter rope (clothesline size) into the cylinder through the spark plug hole. Gently rotate the crank to push the piston upward until you feel resistance. The rope will prevent the valve from dropping while replacing the seal.
2. Put the piston at tdc and install an air hose fitting in the spark plug hole. Set the line pressure fairly low before connecting the hose. Too much pressure will push the piston downward. A little experimenting with pressure before removing the spring might save a bunch of time and frustration.

TexasKZ wrote:

I have read about two methods, but have no personal experience with either of them.
1. Putthe piston a bit below tdc. Thread some small diameter rope (clothesline size) into the cylinder through the spark plug hole. Gently rotate the crank to push the piston upward until you feel resistance. The rope will prevent the valve from dropping while replacing the seal.
2. Put the piston at tdc and install an air hose fitting in the spark plug hole. Set the line pressure fairly low before connecting the hose. Too much pressure will push the piston downward. A little experimenting with pressure before removing the spring might save a bunch of time and frustration.

I'm familiar with methods to keep the valve from dropping (rope trick) the problem is how do I COMPRESS the bucket in order to remove the stem keepers. There's no special tool to my knowledge.
 

Somewhere back in a cobweb infested corner of my memory, I seem to recall a home made rig that used a plate bolted down to the cam cap bolt holes as a fulcrum and a lever with a tube that has a cut away, similar to a regular spring compressor, welded to the lever. The short end of the lever went under the fulcrum plate and the cut away allowed removal of the keepers.

I have heard of folks using a brass rod and a hammer. Place one end of the rod on the retainer and give the other end a sharp whack or two and the keepers supposedly pop out. How it goes back together I have no idea. Seems like a disaster in the making, so if you try this, please make a video recording with sound.

You could use something like this but you would need to fabricate a fulcrum for the hook

 

Could possibly use the other camshaft to hook on.