I'm not real crazy about the four stroke mounts that I've used. It takes more time, but I prefer ones I make from a flat plate, two end pieces of angle (from a bed frame) Two U bolts and two hockey pucks bored out in the center to fit the frame at the seat tube and front down tube. Puck gets cut off for a flat surface to meet the angle iron and drilled to insert the U bolts from the back side of the frame, through the pucks and into the angle which is bolted to the flat plate. The commercial ones are on the expensive side, too. Mine cost a few bucks to make.
SB