Stiff twist action on the up and down rudder controls is usually very simple to address. If you're having problems pulling the twist and stow rudder up and down on your Hobie kayak, first check to make sure you're not trying to pull on the rudder 'up' line when the 'down' line is cleated in (which will make pulling it up near impossible). If the up and down movement of the rudder is stiff and difficult to operate with the up/down lines, the chances are high that your rudder drum bolt has worked itself tight.
To check to see if this is the case, adjust the rudder drum bolt by backing it off slightly (Part# 81399001, as pictured above). Start with an 8th of a turn and see if it helps. If not wind it back another 8th of a turn and try that. Keep making fine adjustments until the rudder moves up and down freely. However avoid loosening it off so much that drums feel loose and wobble about when operated.
If loosening the bolt does not free up the rudder up and down movement, it may be that one of the rudder lines is caught up on something internally. If you're unable to find the source of the problem you should contact your local Hobie kayak dealer
Alternatively consult Hobie's official Twist & Stow rudder repair guide (PDF)