I did some work on the bike today.
First, I looked for a better place to mount the chain tensioner. I think a good place to try is to make a mount that clamps around the shaft collar (the same way the DaVinci Drive does, towards the left). There's space between the freewheel and the dropouts/mounting bracket. Doing so would give me some room for fine tuning: by rotating the chain tensioner mount around the shaft collar a bit, I can move the mount point of the chain tensioner. Executing this plan is for another day, though.
Today's task: Replace the reduction drive shaft. Why? One, because it was nice out and I wanted to work on the back porch, two, because I have the new, longer one on hand, and three... I've wanted to do this a long time. You'll see in the picture below, the shaft I have is about an inch short:
Here's the new shaft. See my scientific way of measuring the fit?
While taking the reduction apart, I found an issue...
Next, there was the 'ol "can't get the shaft out with hand strength alone" syndrome...
Enter the hammer:
Loosened that puppy right up.
Here's the reduction system, with a little bit of winter corrosion. You see the large bely pulley on the shaft, and the freewheel adapter w/ mounted freewheel, a small shim, and a ~8mm wide aluminum spacer.
Check this out: Notice how the hole for the set screw is a few degrees clockwise from the flat I ground in the shaft? Yeaaaaaaaaaaaah.
I could not back that set screw out to save my life. So, I clamped the shaft into my bench vice, and torqued the pulley by hand counter-clockwise. It "came loose", which is to say the flat aligned with the set screw, without tremendous effort. The set screw came out easily.
Notice also in the picture, where the pulley system meets the shaft. That's about 1.5mm deep groove where the aluminum pulley meets the steel bearing inner race. I reinforced this mating area with a 1/2" stainless steel washer, but I don't like how much play there is between the washer and the shaft. I'm going to get some shims from McMaster, shims sit much closer to the shaft.
All put together: see the shaft sticking out the middle of the pulley... Excellent, the reduction is now supported for its entire length.
Here's the other side.