While watching the last episode of the BBC's fairly awful version of War of the Worlds, the one where the writer looked up the plot on Wikipedia and then decided he could do better, I fitted the rods to the J72.
It's a while since I've done this but remembered to blacken all the metal I didn't want the solder to stick to with a thin permanent marker. Then some fag papers were folder either side of the rod and pushed on the crank pin.
The retaining washer was fitted, rod cut to the length and then the pair viciously filed to reduce the washer to very thin.
Finally, a drop of non-corrosive flux and a wipe of solder fixed things in place. 5 or the 6 went perfectly. On the last, the washer gripped the paper too well and so under power, the crankpin unscrewed itself. Digging the paper out solved the problem.
After that, a drop of light oil on every bearing and I was running the chassis up and down my test track. Something more entertaining to watch than the end of WotW.