OK, I have all four pins out of the two left-side upper guides, and I can't get either one out past the chain and sprocket. The chain has some slack in the approaching side; there are several protuberances in the area which hang up the guide and I can't quite slip it out. the outside guide looks impossible; maybe once I get the inner guide out, the chain will slack enough to let it pass. If anyone can offer advice, now's the time. In several years of reading about this repair, I have never heard this difficulty asked about nor mentioned. Now I stop to eat a steak and asparagus, and wait for the Marines.