This is the homebuilt recumbent that I more-or-less completed last season:
It's built up along the lines of the "bolt together" plans that have been available on the web for some time.
This is my more-refined version.
Overall, it works quite well. Comes in at 38 pounds, which is not bad for a bolted-together item. The seating position is quite comfortable, I've got the gearing sorted out so it's useable throughout the range, and the brakes are....adequate. (The cobbled-together front is marginal, but the rear V-brake works well.)
I've refined the chainline since I last posted, the top run is nearly straight now, with that top idler only working to keep the chain from contacting the brake arm.
I only have one problem, high-speed instability. Cruising around on level ground is fine, it tracks straight and doesn't wiggle or pull. However, going down hill is "pucker time". It doesn't do anything really frightening like wobbling, but the steering gets highly sensitive and it does not feel secure at all.
As a result, I have to feather the brakes on even minor hills, and am denied the fun of higher-speed downhills.
As far as I can determine, everything is in-line and the bike has no tendency to pull.
I feel that it's the steering angle; the front fork angle is just too steep.
I don't see any easy way to change that; I'm considering working at the rear end. I removed the "shock absorber" from this cheap aluminum frame and replaced it with a strut. I'm considering shortening the strut a bit. Looks like I can lower the frame at least a few inches without any problem; this might lower the center of gravity slightly and result in a degree or three of increased fork rake.
Any ideas? (I don't weld...)