The original Boge shocks on my Isetta's are in pretty bad shape, so I'll be replacing them.
Building a spring compression tool will really help facilitate the removal of the front shocks. Bill Rogers has a PDF file with dimensions and instructions for building a spring compression tool as well as many other useful resources for the restoring Isetta's on his website.
The original Boge part number for the vertical style shocks on the sliding window Isetta's (as opposed to the horizontal style front shock of the bubble window Isetta's) is ToS 22-310. As far as I know, Boge no longer makes this shock, but thankfully reproductions are available from Oldtimerteile and Isettas R Us.
New reproduction front shock installed.
The original Boge part number for the rear shocks is ToS 22-381. Again I believe Boge no longer makes this shock but reproductions are available from the Isetta parts dealers mentioned above.
Another cheaper option for rear shocks is using shocks intended for a Chevy Luv truck 1977-82. I've heard people say these are too stiff for an Isetta because they were designed for a light truck, however many Isetta owners have used these in their restorations with no problems as far as I know. The one minor glitch in using Chevy Luv shocks is the bottom bolt hole is SAE and slightly larger than the metric size bolt that attaches the shock to the chain case. I simply made a bushing and pressed it into the shock hole to give me the correct fit around the metric bolt. Often I see blue Monroe shocks used on Isetta's which bugs me. I found these black Gabriel shocks on ebay for $20.00 a pair which are a smaller diameter than the Monroe's and are also the correct color. If money wasn't an issue, I'd have gone with reproductions, but since I'm often scraping to come up with the money to do my restorations, I'd thought this was one thing I'd try to save a little money on.
New rear shocks installed.