Not a tandem mechanic, and having an issue adjusting the timing chain tension on my Burley Duet (2000ish I think). I've found and loosened the two allen bolts on the front BB shell, and I've tried tightening the chain tension using a Park Tool pin spanner (the green-handled one I think) inserted in the pinholes on the right side of the BB, but this does not seem to be tightening the chain tension...Am I doing this wrong? I can press on the chain to increase slack (once released), and I can rotate/push the crankarms forward to take some of the play out of the chain, but there still seems to be more than 2" of play in the chain at it's tightest through a rotation of the cranks (i.e. this is the best it gets).

Thanks,
LKW