Not too long ago the cylinder head on my c900 blew the gasket. I figured while I had it all apart I would check my lifters for sticking since they would normally be noisy while its first started and one would stay noisy when ever it liked. I realized that with the lifter out and the oil port facing down I could pump out the old oil (which was old and nasty) by pumping the center piece in and out with a set of pliers being careful not to nick anything. Once I got the old oil out I submersed them in a solution of 3/4 parts lucas oil additive and 1/4 the synthetic oil I usually run. then I began pumping them again with the port aiming up while still submersed until it stopped spitting up bubbles. then I positioned the port of the lifter to the oil ports of the cylinder head. Of course at first when I started the engine for the first time after repairs they where quite a bit noisy but once they became completely filled they have not made a single click noise since. not even after letting it sit for at least a week. they also have 170k miles on them. I hope this helps some one or at least it may be worth the effort on your next top end repair.