Yep, certainly have and it's a right pain in the a***.................Honda's method according to the 'Official' workshop manual makes good reading but nothing else, remember that this was a 'budget' bike that Big H thought would be discarded after a very few years never to be resurrected never mind thirty years later. The shafts are secured in place by parallel pins driven into the cam cover with very little access (I got my replacements plus shaft 'O' rings from David Silver) and this is how I shifted them...........Using a Dremel or equiv., undercut slight 'vees' in what part of the pins that you can get at, opposite sides obviously. Clamp the cover in a vice (tightly) and apply a pair of Mole 'vice' grips onto the pins as tight as you possibly can and then using a 'drift' against the jaws of the grips, hammer them away from the cover to draw the pins out. the grips after this abuse could well be scrap, mine were. CMM recommended the use of heat on the cover which is probably a good idea but be careful as the alloy (?) used is c**p and can distort or even disappear in front of your eyes as you're doing it. This really is brute force and goes totally against the grain with me but there's no real alternative that I can think of. This is a lot of hard work to replace two 'O' rings that cost next-to-nothing. Best of luck, pleased it's you and not me again !.