Hey, new Serpent owner here. (I blame Steve) I picked up a pair of used S411 v1 and I've got questions about how things go together. Be gentle, it's my first grown up TC.
I'm using an Arc 64p 96t spur gear, with a 47t pinion, to start out with an FDR of about 4.1. The first problem i ran into was mounting the motor. With the spur in place, I couldn't get the rear motor screw into place. I ended up removing the motor mount, attaching the motor to it and reinstalling the assembly.
The second issue occurred when installing the pinion. In order to fit the pinion in place, I had to loosen the rearward section of the top plate to gain clearance to slide the pinion onto the motor shaft.
Thirdly (and finally) was setting the mesh and tightening the motor down. The forward motor screw was easy enough to reach, but getting to the rear screw proved difficult, as the spur gear was again in the way.
I guess I'm wondering if I missed something or did something wrong. Should I have invested in larger spur gears? (I call it invested, as these things were $10 each!)