Achipmunk...that's their stated purpose. Ten pounds for drums (return springs like "Hotrod" said, and 2 pounds for disc. I checked for residuals in the M/C body using a wood dowel (actually a wooden Q-tip). Carefully insert in the outlet ports. If it just goes a short distance(say 3/16" or less) then there are valves in the body. If it goes in 1/4" or greater, then no.
As to other questions... The 7/8" bore is due to the smaller than I would like booster (under floor setup with limited space). Residuals valves because my M/C is level/lower than the slave cylinders. And lastly, I called a supplier of performance brake part/systems to the hotrod world. They stated residuals always go after the proportioning valve. I didn't ask why.
