you should only need three mounts the lower one on the seat down tube holds the pillow block and the motor mount you will nee to drill 2 holes for the engine plate. i dont think you will be able to fit all three on the seat down tube. maybe you have a different plan? looking foward to seeing your build!!! i will be posting pics of the schwinn soon been working on the gas tank and clutch. put in some different shoes for engagement hopefully it helps.
good luck
glenn![.wee. .wee. .wee.](https://motorbicycling.com/images/smilies/wee.gif)
good luck
glenn
![.wee. .wee. .wee.](https://motorbicycling.com/images/smilies/wee.gif)