Hi mtang, - whilst you've got it in pieces... thoroughly recommend upgrading the electrics; -
A DECENT (12v 300W) alternator conversion; - suggest: https://ironhorsespares.co.uk/square-four-alternator/
beware of lesser alternatives!
Have the distributor modded c/o Kirby Rowbotham to remove the points & advance /retard: firstname.lastname@example.org
& fit a Boyer Bransden electronic ignition: http://www.boyerbransden.com/
Such mods will enable you to see & be seen... & keep the motor running!
Should you require the machine to actually stop when you apply the brakes... please don't fit a disc 'cos they're so out of context...
... if you can get hold of one; - fit a Grimeca 230mm 4LS ~ looks the part, no mods to the forks required,
& exceedingly effective when correctly set up.