Originally Posted by Paul L

Nhra: Hi, i used a 100 spur. you can use a 104 also. Xray is making smaller gears, but for now you will have to use another brand and make it work.
I used a Kimbrough and sanded it thinner (took 5min) to fit, then drilled a hole in it for the motor screw. The hole will have to be pretty close to the outside teth. it seems like a pain but its not that bad.