I have uploaded pics of my bike on here in a previous thread in an effort to identify it and shed light on it's age. Through my research (on here and elsewhere) I have come to believe the following.
1. Motobecane were running orders of bikes off that cleary do not correspond to any of the bikes in the US catalogue models.
2. No Motobecane should have reynolds 531 but not Nervex or Prugnat lugs according to the catalogues (US) but the French catalogue introduces a "C" and "T" line that has 531 3 tube and also has 531 forks and bocama lugs and Shimano 600 brakes. The top of the line T in the late 70's also had a Stronglight spidel.
3. There is no consistent serial number to identify the model, age or place of construction.
4. In the late 70' Motobecane were the first French manufacturer to use Shimano Parts making the first run of these bikes possibly the most collectable?
5. The grand jubilie, grand record etc never appeared in the french catalogues and only manifest as American models. The French catalogues only state the series and then break the models down into numbers.
If anyone has any more information about these bikes please share it here. And can we try to get as many serial numbers in one place as possible?
I am avidly into this brand now after researching so much. But want to take this a step further.
Cheers for the great posts, class forum.