Originally Posted by
bertinjim
I suspect it would be dangerous to ride. I also suspect it's a homebrew tandem made from singles. The fork brace has failed but is a two piece brazed together botch. The rear bracing stays behind the captain's BB and extending to the stocker's seat tube are made from two crimped stays brazed together. As well, there is no eccentric BB to allow chain tensioning. Finally, I think the homebrew decals say Manufearn II (to match the headbadge) not Manufrance. However, there are good bits on it and it would be worth plundering for parts.
I agree that it looks like a homemade joining of two singles together. I thought that even before you pointed out the lack of a front eccentric BB, which I had not noticed. With your observation about that and about what is passing for a boom tube clinches it for me.
It's value, IMHO, is as one or both of (1) a parts donor or (2) a curiosity. It certainly is not a rider. It may hold up, but I would not be willing to take the chance.
I'd be interested to see if it has an actual tandem crankset or just parts from singles. My guess it is the latter, in which case the pedal threading would be backwards for three of the four crankarms. If that were the case, God help you if one of those three pedals had their threads seize up while riding it. It's been a (very) long time, but I have had a NDS pedal simply freeze up. The result was unscrewing the pedal with my foot strapped in. Annoying as hell, but not more than that. But if the pedal threading were backwards - at least a crash and possible nasty bone or ligament/tendon damage to the affected ankle.