Hi and Merry Christmas everybody!
I have a problem with my Sho Bud Pro III RKL tuning. When I try to adjust the amount of the pitch change of RKL both 1st and 7th strings' pitch changes as I turn the screw at the end of my steel. So I'm not able to tune the actual mechanism because just 1st and 7th strings pitch changes. The function of my RKL is standard on E9-neck. I'm confused and don't know how to fix the problem. What could be the actual reason for this? (it's hard to explain in a message
It sounds like your problem is either loose return springs or lack of free play. First, look to see if the lower fingers move when the knee lever is activated. If they do, tighten them up one or two turns until they don't.
If that's not it, back off both nylon tuning nuts so that neither change the pitch of the strings when the knee lever is activated. Tune the strings open, then tighten the tuning nuts to bring the strings up to pitch when activated.
If that works your problem is solved. If not, you will need to adjust the knee lever stop to allow for more travel. Do that and repeat the above steps.
If you still can't get enough travel, you'll have to move the pull rods one or two holes up (away from the cross shafts) and try again. This will give more leverage to the pulls and make them pull further with the same length of travel.