From GummyCarbs

Spoked Wheels

Sealing for Tubeless

Spoked rims often don't have a channel for the bead of a tubeless tire to pop into. This is critical to keep the tire in place when running low pressure. However, this site makes the argument that the ridge is actually only there to help seat the bead initially. Personally, I ran a 1977 CB750F2, which had early tube-type Comstar wheels (aluminum rim with five stamped 'spokes' riveted to the rim), tubeless.

This post shows a conversion on a CB-X wheel that doesn't have a ridge. They warn not to allow the pressure to drop below 1.6 bar (23.2 PSI).

This post shows the process of sealing BMW R1200R rims using a kit from Outex.