The bell crank has (or had) a little stub sticking into the axle thread which limits how far onto the axle it threads. This then locates the bell crank and it's lever WRT the indicator rod end so that when in 2nd gear the red mark will be centered within the window. It this stubby is broken and/or the bell crank is threaded past this point the gear adjustment will be off if the red mark in window is followed. Another method for adjusting the cable/gears is to use the cable adjuster so that 2nd gear is lost and 1st gear starts to engage. mark that point on the adjuster threaded shaft then back off the adjuster past 2nd gear and into the start of 3rd engaging. The half way point between 1st and 3rd is about where you want the adjuster to be for a centered 2nd. The bell crank usually has a thin lock nut which helps to keep the bell crank in place when removing the wheel. Andy.