Make sure after you adjust your throttle linkage you should have very little/no play at the back of the rod connection/firewall with wide open throttle on the carb. I adjusted mine today as it was shifting too early out of first for my liking. Had a little too much free play and I took that freeplay out. 1st gear now shifts 5-8mph later and firmer due to the higher rpm range at light throttle.

You'll get better shift points when it's properly adjusted.