Proportioning Valve for the Rear RSV Caliper

Folks,

I’m finished with this project and I am happy to report that installing a proportioning valve in-line to the output side of the master cylinder, has exceeded my expectations. Attached is my analysis of this project.

Rick

Just an update to this project,

In my original analysis, I spoke of another valve I had found on-line from Speedway Motors that I felt would work out better than the Wilwood valve I used on this project. And I mentioned that I had no first hand knowledge of how this valve would work and that someone else would have to investigate this valve.

Well after I went down again with another rear-wheel lockup (even after I had already changed out the rear brake to a 2-piston caliper) I decided to see how this valve would work and installed one along with a new rear Galfer stainless line that I described in the above analysis.

And it worked out just as I had felt and it installed much better than than the Wilwood valve by the fact it is a more straight through design. However, the adjustment knob is much freer than the Wilwood knob and really needs to be drilled and safety-wired. But just one special note on bleeding the rear line with this valve. With the valve completely closed it will still allow fluid to the caliper but will not let it bleed off quick enough when the pedal is released, thus locking the caliper to the rotor. Therefore you need to open the knob up at least one turn when you first install it and it will bleed and work just fine. Then adjust it to where you feel comfortable. I went with 2 turns out. Below is the link to Speedway:

http://www.speedwaymotors.com/xq/aspx/display_id.1979/itemNo.91031357/qx/Product.htm

There is one other situation I can across when installing this valve, and that was getting a good seal between the copper banjo washers and the adapter. I was getting a weeping seal on one end and when I took it apart and checked the mating surfaces, I found a small ding in the end of the valve that wasn't letting the washer seal. But I just lapped the end down below the ding with some fine sand paper on a flat surface, and it sealed up just fine.

I've attached top and bottom pictures of this valve installed. And if any of you want to install this valve, just drop me a line and I'll help if you have any questions.

It is really comforting being able to press down on the brake pedal and have the bike slow down without hearing a screeching rear wheel.

Rick