I'm not sure what the actual name of these are, but I'm trying to get my cable-tension shifters (I think this is one of the first shifters that come on five speed bikes, tension on the cable pulls the shifter toward the lowest gear) dialed in to where the bottom of my shift lever is my lowest gear ratio, and the top of my shift lever is my highest gear. After setting the tension by positioning the lever and the shifter, and tightening the cable clamp on the shifter in my lowest gear, I got it reasonably in position, and then adjusting one of the stop screws to limit its travel to my highest ratio. I have found the other screw next to the first has no apparant effect. I'm wanting to use the full shifter lever's travel, but now am using about the lower 50% in this configuration. How would I go about tuning these shifters properly? All my other attempts as of yet would end up pulling the chain off my rear cogs, which makes riding quite interesting.