It's going to be tough to convert to USS for a Speedster:



First off, there is no a whole lot of room between the seat and steering column, so you might have to go to a handlebar that's attached to the fork.

Since your current fork is not likely to have a mounting point for handlebar to be attached to, a new fork may be needed, or modification to your current for is necessary.

Second, you will need a handlebar that is long enough to reach your hands and wide enough to fit your seat and have room to steer. With the original wide seat of the Speedster, you might have a hard time finding a handlebar that would clear.

I would recommend you keep an eye on craigslist for used USS recumbent instead of converting your Speedster.