Picked up a Mark I Excelsior Welbike the other day here in Austin, Texas based on a lead from Colin Stevens. It supposedly sat inside the seller's home for the past ten years and he never tried to start it. It had been in the home of the person he got it from for an unknown amount of time as well and again, had supposedly never been started.
Spent a few hours checking things out, filled it up with engine oil and the proper 16:1 fuel/oil mixture, then some additional time tightening all the fittings, bolts and fuel lines that were leaking. My guess is someone in the past had disassembled everything to paint it and then reassembled it with everything looking more or less new. Nothing was tight since they never put any fluids back in as it was to live inside and not be used.
Have a video clip below my wife shot with a regular digital camera. Bike smokes a bit and obviously has a few things I need to still adjust. The camera had a fixed focus but caught the run OK along with her running commentary if you have sound . I get no respect
Might take a minute or two for your computer to buffer the video before it starts as it is 13MB total lenght. Course this is if you have a high speed connection. If you are on dial-up, it might take a few hours to start.
Welbike Video