I'm years late to the party but wanted to share my experience with this identical issue for anyone dealing with this in the future. I had the issue of my cable seemingly too long no matter what I did, like inches too long. It didn't make sense because the bike had been ridden and I could see by the rust where the cable had been originally adjusted.
Long story short, I think the issue comes because the clutch spring arm (the thing that you attach the clutch cable into and secure with a cotter pin) is oriented incorrectly. If you imagine the cover to be on the bike, that arm actually needs to be pointing toward the rear of the bike. When installing the arm, it's not apparent where it should be pointing. Initially I had it pointing toward the front of the bike. That's what creates all the slack.
So... Readjust all the screw adjusters so they're back to where they were based on the rust lines. Slide in the adjuster arm so it's sitting over the three ball bearings BUT facing towards the back of the bike. This should take up the mystery slack that was on the cable.
It should fully seat on the bearings, sitting flat in the cam. The idea is that it's sitting flat now but when the cable pulls it, the assembly will rotate on the cam and lift up, applying pressure on the clutch rod.
Carefully reassemble, making sure everything stays in place as you reinstall the cover and cinch it down tight to the engine case. There must be no space between the cover and case. Hope this helps someone. Good luck.
