If you look through this manual for the 1980 D50 chapter 14 page 9 starts discussing the carb and mentions vacuum hose routing without showing a diagram. It also refers to Chap 25 Emissions Controls I didn't read closely but you may be able to help yourself that way. I suggest you actually try inserting a wire or small drill bit or failing that spry in some WD or carb cleaner to break up whatever is plugging the holes as directed. The long time members on here aren't going to tell you to do something that will hurt your motor.
The Manual http://www.mightyram50.net/vbulletin...ory-manual-PDF I have a hard copy of the 85 manual and its pretty much exactly the same with a different cover.