Before I wander away from the subject of tandem maintenance (which, admittedly, is interesting to about 3% of my readership, a.k.a. 0.1 people), I thought I'd share one more trick that until recently had me stumped.
Last season, I was tweaking the tension on our 'dale's timing chain and accidentally derailed the thing. And, no matter how hard I tried, I could NOT get that stupid thing back on with the cranks in phase. I'd seat it on the front timing ring, align the cranks, and somehow get 1-2 teeth off as I seated it on the rear timing ring. I must have fought that stupid thing for hours, finally accepting a "two teeth out of phase" setting and searching the interweb tandem forums for a way to justify it.
(Aside: You wanna start a holy war? Wander into a tandem forum and argue for ANY kind of crank phase... in-phase, 90 degrees out of phase, 180 degrees out of phase. It doesn't matter. Whatever you pick, there's a faction that will agree with you with religious fervor, and an equally-devout faction that will question your sanity. It's one of the many reasons -- not to mention the propensity for matching jerseys -- that I stay away from tandemers in groups, whether in person or in the virtual world.)
This season, I knew I was going to have to tackle the timing chain beast again, since curing the Cannondale Creak was going to require pulling both bottom brackets. But this time, a light bulb went off: When I was ready to reinstall the chain, I found two toestraps (fun fact: auto-correct calls them "toast wraps") and used them to snug both drive-side crankarms (thus, opposite the timing chainrings) parallel to the seat tubes. Installed the chain, took off the toast wraps, and voila! Perfectly in-phase. (If your particular tandem jihad worships an out-of-phase setting, you'll have to figure out how to modify this technique accordingly).
Maybe this trick is painfully obvious to those who haunt the tandem forums and tandem shops (and I'm sure Santana's Bill McCready -- the Gary Fisher of tandems -- invented it), but it was new to me (and saved me from pulling out what little hair I have left), so I thought I'd share.