On my "new" prosjekt, the igniton key was lost. I have both types. Chicago and B&S / Yale.
On my Thule ski holders ,I find drums who fits very well in the cylinder.It's not easy for me to explane,but I think the pictures will talk.
If you have a B&S (upper),cut of the front of the drum and use this. If you have a Chicago (lower) ,make a drum from a pice of brass.
You most adjust a little inside the drum with a file. Use a dremel or some rotating file to do the square hole.
The locks works great for me :)
Regards
Arvid
http://www.chevroletnorge.com