I’ve been asked about shifter upgrades a few times lately and decided to post something here. This is the first draft.
Here is a diagram of the shifter:
The “shifter bushings” you always see advertised are the parts that replace parts D and E. They are on either end of the rod that attaches between the transmission and chassis and holds the base of the shifter in place. Since this goes between the drivetrain that moves around and makes noise there needs to be a bushing there to absorb nvh and allow drivetrain movement. Putting in stiffer parts like the kartboy front bushing reduces the amount of bushing deflection you get while selecting a gear. So forward and back movement gets a much more direct feeling because the stock squishy bushing isn’t moving back while you try to move the shifter forward. With these bushings you actually get some feedback out of the shifter and can feel the syncronizers and dogs engage. Some people call this “notchy” like that is a bad thing. IMO it is how the shifter should feel.
For side to side shifter motion, the u-joint linkage comes into play (parts A on the diagram). The bushings wear out and suddenly the stick has to move a long way to either side before anything in the transmission goes anywhere. Here is the linkage:
There are a couple of different variants of this linkage. Early ones have an external centering spring, some are riveted together, and some use different sized bushings. For later cars where things bolt together you can just buy the bushings for like $20. For older cars with a riveted linkage but without an external return spring you can buy the updated linkage, or drill out the rivet, replace the bushings, and put it back together with a bolt. For older cars with an external spring you have to drill it apart and replace the bushings yourself. I picked up some 3/8″ nylon bushings from mcmaster carr plus a stock linkage bolt. Had to ream the bushings out slightly to 10mm but it works pretty well.
Drilling out the linkage:
The bushings (you need 4) and new bolt: