1974 sportster

[harleymike151]

please could tell me how much to fill primary ? what is the best fluid?

 

[Webbtron]

It is difficult to discribe but with the bike level, there is a screw that sometimes has a brass washer kind of above the kickstand. Fill gently till it comes out that hole. you can start with a Pint and see but I believe it is 1½ pints. Just go slow because it will take days to weep out of there when you go overboard.
Oil is your choice, I use Amzoil 20/50...used Valvaline 60 for years.