Joints moteurs ABC Gnome et Rhone 500cc et 400cc

Bonjour à tous,
Pour mes moteurs ABC Gnome et Rhone 500cc et 400cc j'ai fait refaire l'ensemble des joints par JPM83 (https://jpm83.fr/) bien connu en France pour son sérieux et la qualité de son travail.
Pour cela j'ai scanné tous les plans de joint et reçu en retour des joints prêts à monter.
Après quelques ajustements, je peux maintenant remonter mes moteurs et je comprends que de cette collaboration des ensembles de joints sont maintenant directement disponibles chez JPM83 pour les moteurs ABC Gnome et Rhone 500cc et 400cc.
Un grand merci à Remi de JPM83 qui m'a toujours très bien accueilli et conseillé grâce à son écoute et son expérience.
Amitiés motardes

Ça a l'air d'un bon travail. N'hésitez pas à partager des photos de toutes les pièces au fur et à mesure de l'assemblage du moteur. Merci

This discourse has reminded me of an issue that has long been at the back of my thoughts...the degree of metrication of the Gnome et Rhone version of the ABC motorcycle.
Of course, all screw threads were metricated (no more BSF! Bye-bye BA!) and also all ball bearings (noting that, to this day, the actual balls in a lot of metric bearings are to Imperial sizes!).
But what of the rest? It would have been natural for G&R to have rationalised the dimensions: they would have been rounded up or down to whole millimetres or simple fractions thereof. 
Which leaves us with the question, admittedly academic, of the interchangeability of Sopwith and G&R components. And NOT academically, of whether these French gaskets will fit our British bikes!
The one person I know who could resolve this matter is Peter Gillespie, creator of so many high-quality replica parts for Sopwiths. So, over to you, Peter!

Now that I am no longer riding my interests  have returned to clocks and cameras.  I bought an 1899 British  wooden quarter plate camera from my local Oxfam shop where I work pricing old and interesting books, but that is another story.  I had to repair the wooden front panel and make up some missing brass fittings.  It also needed a couple of screws one of which was 3BA that didn't quite fit.  When I measured it I found it was metric 4mm which is astonishing given that the camera was made in Birmingham.  Subsequent research revealed that all of the screws were metric and that they were the standard on the other British makers!  The metric standard thread system was established in Geneva in 1896 and it is likely that the early British camera manufacturers followed the French designs including their brass screw fittings.
The first motorcycles were produced in France with metric threads and when BSA started to export their fittings to France their offered both metric and imperial sizes of tubing and lugs so the mixture is not surprising.  Morris took over the Hotchkiss factory, who had been making their engines in 1924 using metric threads, which is why Morris engines used metric threads with imperial heads right up until the post war years when Leonard Lord used Austin engines with imperial fittings.