Look at the check ball in the oil pump, common issue. Make sure you get a small enough carb for it too, a very common mistake made on those was to try and put too much carb on it. I have always been an antique Brit mechanic but most of my friends are HD and a couple own shops so you can't help but pick up some stuff.

I learned all I need to know about life by killing smart people and eating their brains.
Eat right ,Exercise ,Stay fit, Die Anyway!