I put in a later reed valve breather and hose, and removed the old disk breather that was on the bike, and then put the cylinders back on. Several articles mention that you don’t need a piston ring compressor. They dont’t mention how painful pressing them in with your fingers is!

Up Next! https://kirkusblog.com/2011/01/19/das-bike-projekt-take-er-down-spin-er-around/