Check out mechanical engineer and inventor Guido Koch’s home spun 2wd KTM 990 Adventure with new custom frame with front swing arm and hub-centre steering system.
Guido is now looking for investors to help fund developing this into a kit for sale to the public and/or to build complete bikes for sale.
Wunderlich Hybrid BMW R1200GS LC with Electric 2WD
Here’s a selection of home made 2wd projects, including a DR200/250 with switchable front wheel drive.
https://www.youtube.com/watch?v=xlI40RLyytk
Here’s the Youtube channel of a guy working on a 2wd system for the KLR650.
https://www.youtube.com/channel/UCrEdyFcfeDdmSys7cMCrkiw
Claude of Freedom Sidecars in the US has also stated they are working on a 2 wheel drive system for the KLR650.