When I ride I like to have footwear that covers my ankles to protect them if something unexpected happens. I bought some boots that had more padding than the basketball shoes I used to wear. But the boots have a heel instead of being flat the length of the bottom and that placed my foot lower on the peg and made upshifts more difficult because my foot likes to ride on the peg just in front of the heel of the boot.
I tried using a 10mm wrench on the linkage to adjust the shift lever downward but ran out of adjustment before it was at the optimum height for my foot. So I marked the end of the shaft that goes into the trans. with a mark in line with the split in the little arm that is bolted to it so I would know how the arm was originally oriented on the shaft. Then I removed the 10mm bolt from the arm and slipped it off the shaft and rotated it one notch downward, then replaced it on the shaft and tightened the bolt.
This gave me more downward adj. for the shift lever and I was able to lower it enough to make shifting with my boots comfortable and made positve shifts a lot better. With the shifter adjusted properly for my boots shifting is a lot better and I don't have trouble with the 4-5 shift anymore.
Just thought I would pass it along. Make sure you mark the end of the shaft so you can put the little arm back to its original position if you decide it doesn't work better for you.
When you loosen the two nuts on the rod (they loosen different directions so look at the threads on the rod to see which way) you can turn the rod with your fingers and move the shift lever up and down.