Rear Master Cylinder Relocation

The rearsets are Sato type 2 shown here

http://www.satoracing.com/rearsetsrsvfactorytype2.htm

You use the standard master cylinder relocated onto the sato rearset

Relocation options are Sato or Gilles both of which are expensive new.

Fusebox has some custom made ones on the way which are a bit cheaper. I have just sold my Gilles for £200 odd as a guide to seconhand prices.

Why bother, my rear brake works fine and has done for 6000 miles + just an expense you dont need IMO :confused

I found that mine has had the master cylinder changed to a nissin and so i've never had a problem with the rear brake

I got a heat shield on mine and the fluid is fine, maybe try that first, £7 i think or make one up

Well mines the same parts so it needs to be bled correctly, takes a bit of getting used to but once you got the nak its easy

Ya dont just turn it upside down, you need to tilt it a few different ways to, sounds daft but i worked for mine 6000 + miles ago and still is fine, you have to make sure ALL the air is out

Did you open the up the tube from the resevoir to 4 mm from 3 mm i think it is, do a search and you may get some more info

OH and also the fixing holes on the master cylinder can be made bigger letting you tilt the master cylinder forward so to help the self bleed

hanging a weight off the rear brake pedal over night was the cheapest mod I did!! :thumbup

The brake problem seems to affect some bikes more than others regardless of bleeding technique. The post 04 bikes especially have a higher frequency of brake and Radial Clutch M/C issues.
My first Aprilia went 9k and i never bled it. My 2nd went 50 miles and no brake and then had to be re bled every 2k or so.
It had all the updates and Aprilia shoved it to 3 different dealers in an attempt to get a fix back in 2004.
Same parts, same bleeding technique but relocated to Gilles and 100% back brake 100% of the time.

That's not the black and white answer it seems as the problem seems to be partly the oem seals and partly the fact that it's pretty much impossible to have fluid with no air in it at all. Most fluids will have tiny air bubbles in it from absorption or agitation. Without heat those air bubbles wouldn't cause a problem as they are so small but add a decent amount of heat and they expand and collect together.
Relocating the M/C reduces the heat on the M/C greatly so the brake becomes much more tolerant of small amounts of air in the fluid, but it is a fix if all else fails.

The key thing is to use new fluid if poss not something that's sat opened in the shed for 3 years. Let it stand for a decent time to let air rise out of it if it's been bounced around in the post or something. Then use the bleeding technique mentioned in previous posts.

If you ride in high temps or traffic it's much harder to get a permanent fix with the stock parts. The Radial Clutch M/C doesn't have ver heat tolerant seals and often lets air into a competenly bled system. Someone on af1 measured the clutch slave after a ride in traffic at over 300 degrees. That's a lot for the fluid and seals to cope with on a regular basis. The Aprilia USA race bikes all run non radial M/C which have a smaller stiffer seal.

It's not much consolation but the brake/Clutch issue has affected Ducati and MV bikes as well so it's not Aprilia dropping the ball. MV relocated the M/C on subsequent models, not sure what if anything Ducati did. Aprilia now have the M/C on the rearsets on the new rsv4 etc and a cable clutch.