Before going to the trouble of fitting this, think about why the choke is so stiff to begin with!
Mine used to be, and my console is indeed cracked. However, if you disconnect the cable's at the carbs, more than likely they will move much easier, which obviously isn't unexpected as you are no longer trying to overcome any mechanical connections at the carb.
But by oiling the cable's and checking the small fuel pipe from float chamber to the jet is not overly stiffened with age, you can much improve the operation.
Prop the cable end's up in the engine bay as vertical as possible, and then carefully and monotonously slowly, drip light oil in the ends. You don't need a lot, try 10 drops per cable, move the lever back and forth a few times, try another 10 drops, re-check etc. It goes without saying that you should also check for kinks in the cable, especially where it runs beside the heater pipes and valve and out through the bulk head.
Also check the smooth or not, up and down movement of the jet, if it's binding at all, use some very fine wet emery paper, and CAREFULLY rub the jet by wrapping a small piece of said paper around it and then gently and briefly, move around the jet with the lightest of pressure!
Rub, clean, fit, check movement.... repeat
My console still creaks a bit, since it's already cracked, but the choke lever moves much easier and smoother than it ever has before.
The above relates to Hitachi's but SU's are as many already know, very similar, although the fuel pipe from float chamber to jet is a much better arrangement IMO and suffers far less from any stiffening!