Been working on this little classic. Swapped out the shorty intake for the stock 4" bendy one.
The change in the power delivery just from lengthening the intake tract like that is pretty shocking. Lost a few MPH on the very top end, but gained throttle response and ridability all through the power band.
That's a 1979 Motobecane 50VL with a SIM pipe, 16mm SHA, and ported cylinder. Still not quite where I'd like it overall.
What I really want is the AV10 Reed inducted cases, and a nice burly 74cc cylinder. You know, when I have another $500 to drop on it.