. . . . . just a brief additional note? An old trick, used by old mechanics, working on old motorcycles that had experienced an old, busted drive-chain: It can be a real bitch to replace a chain, usually due to fairly close clearances & inaccessibility of sprockets, etc. The first time it happens, hopefully you've got someone that's been there, before. The suggestion was to attach one end of the NEW chain to one end of the old chain. Then, as ya slowly pull the old chain off/out, it draws the new chain into place. VOILA! We later applied the technique when replacing aileron cables on a flying machine. We still had to remove many under-wing inspection panels to verify that the cables had in fact gone where they belonged ~ ~ ~ over pulleys, through guides, etc. Butt, we did NOT have to try to get our hands up into those damned close quarters, scrape knuckles, curse, etc. to install the cables! The next day we were replacing electrical wiring from a cockpit to a nav/posit light on the vertical stabilizer. Guess what technique we used? s/s An Old A&P ORL/MCO