I need to know how to get the primary clutch off. I can't seem to get the nut off that holds it on. Is there a special way this needs to be done? Also, how can you tell if the primary is worn out?

 

I've always used a impact. Maybe holding on to the centrafugal tightly will let you get that off, but it will be even harder to tighten it because the hole clutch basket free wheels while turning it in the other direction. I suggest trying to find a impact.

The centrafugal is even harder to get off.

When you do get it off look at the depth of the grooves in the friction plates, they pretty much tell how much is left. The steel plates are sappose to be clean, no black spots. If the clutch has been slipping excessively the steel plates will be black instead of shiney silver.