I just found a Kappa “Zippy” K46l monolock top case on Facebook Marketplace for $30. It’s an older (ten years?) 46 liter Kappa monolock case off a 2013 Honda PCX150. I had read some comments about monolock units only being intended for slower speed, smaller scooters, but for $30 I figured I’d give it a try.
I didn’t want to spend the extra money for the Silverwing specific Givi or Kappa monolock mount, so I went ahead and mounted the universal monolock mount that came with this Kappa top case.
The universal monolock mounting plate went on pretty easily with four bolts with just a little drilling and trimming of the plastic grid to fit the two rear mounting holes in the Silverwing rear metal frame.
I just added a couple of washers under the two forward bolts between the monolock plate and the Silverwing frame to account for the curvature of the metal frame, and the assembly is a lot more solid and sturdy than I thought it would be.
I’ve read some discussion that the monolock units and their mounting plates are for slower scooters, and the monokey units are for street bikes with higher speeds. But judging by the quality of this Kappa 46l top case and how solid it’s universal mount installation turned out, I have no concerns about using this monolock case for interstate traveling.