I've been tinkering with the brakes on the Spada 3 again. I was having issues getting any rear brake activity and I'd kind of given up on it for a while as I didn't seem to be getting anywhere and came to the conclusion that either the master cylinder or the proportioning valve were kaput, and neither were available at the time: the master cylinder is at least still made, but not the valve.
Last week, I managed to track down a master cylinder in Germany and it arrived the other day, so tonight I fired up the garage heater & set about swapping them over. I've spent a while now trying to bleed the system and it's just not playing the game. I'm using my big vacuum bleeder which works on compressed air and I'm not getting the volume of fluid coming through that I'm expecting, so I'm now thinking the proportioning valve is the issue after all. This leaves me with a bit of a dilemma: do I continue trying to keep the linked brakes or ditch that & convert it to conventional.
To keep the linked brakes, I'd have to either replace the valve with a 3 way t-piece, or see if I can disassemble the valve & fix what's wrong with it. The V50 doesn't have any form of proportioning valve in it's linked brakes, so I'm fairly OK just doing away with it if it comes to it.
I don't know what I'm going to find inside the valve, or how it would come apart to that matter, and there's no rebuild kit. I'm thinking that there will be a piston and springs the fluid pressure will work against to restrict the amount going to the rear as you increase the pressure.
Before I set about stripping it though, I've bought a cheap 3 way block I'll stick in its place to see if I can get any better bleed activity and I'll blow out all the lines as well in case there's a blockage somehow.
Converting the whole system to a conventional layout would only take 2 new braided lines as I think it's the 13mm piston in the front master cylinder so should be big enough to feed both calipers.
I'm reluctant to convert the brakes as I'm probably looking to move this bike on this year and I'd prefer it to be original, but original & not working isn't going to cut it.
Let's get the 3 way installed & see if I can get anywhere & take it from there.