Rear brake modification

Im with kemille on the clutch problem, I need to bleed mine every 2nd or 3rd outing, about 500 miles, its simple enough to bleed the clutch, but when spending £5000 - £7000 on a bike, ya shouldnt need to fork out for a lifetime supply of clutch fluid and be permanantly in ya tool box. :rant

There is a mod you can carry out on the rear master cylinder, invloves enlarging bores with a drill as far as I can recall.

Mate of mine has done it on his Edwards rep and his back brake has been fine ever since.

I bought a used rear master cylinder on fleabay about a year ago with the intention of doing this but I'm a lazy bast and haven't got around to doing it yet.

I'll look up the details and post back in a bit.

TarkMalbot said:

I thought they were tyring to resolve this and there would be a recall?

Click to expand...

I received a letter from Aprilia referencing several 'complaints' and 'bad write-ups' about RSV Mille and Tuono Mille rear brake and they've carried out investigations by a 'Task Force' of engineers and experts.

Bottom line:
"After much analysis and testing the Task Force has now concluded that there is in fact no defect ofdesign or manufacture, and that the brakes are completely safe and fit for their intended purpose.
However there does exist the possibility that any sponginess could be caused by incorrect procedure or materials during servicing.
Therefore, should you have any concerns regarding the rear brake, we invite you to contact your Aprilia dealer to make an appointment to have it thoroughly checked. This will be done at no cost to you."

Sounds like we're all WRONG according to Aprilia:rant and definately no recall:exclamation

There is a simple fix, the service bulletin lays it out nicely and gives nice explicit directions to fix both. Here is a link to kzmille's post at the AF1 forum. Go there, do exactly as he says and your rear brake will be sweet. I also redid my clutch slave and after 300 miles I still have clear fluid. The man is good, you don't really need special tools to get a good bleed on the rear.

"After much analysis and testing the Task Force has now concluded that there is in fact no defect ofdesign or manufacture, and that the brakes are completely safe and fit for their intended purpose.
However there does exist the possibility that any sponginess could be caused by incorrect procedure or materials during servicing."

You must here be able to read between the lines, they're saying that the parts they're using are perfectly allright (i agree) and that the problem is with the procedure...(i agree) they're using at the factory. I've never visit the factory but i'm assuming that after all the rear brake parts have been assembled (disc, caliper, hose,lever,master, ect.) then somebody proceed filling with brake fluid as it is install. The problem is you cannot properly bleed the system the way it's installed as air has a natural tendency to rise in a fluid. The bleeding nipple would need to be at the highest point along the path between the master and the caliper. As-is the nipple is about the lowest thing in the line while the highest point is somewhere in the middle of the hose line. So in order to properly bleed the line you have to unbolt the caliper assembly and put it in such a way has to have the bleeder at the highest point along the whole path. Then the air will SLOWLY rise and migrate to the top (bleeder) when you bleed you will have manage to remove all the air and should have no more problem EVER.Hope i can be of some help but If i'm somewhat unclear come back for more.:thumbup

rear brake

I forgot to say in order to put the bleeder at the top of the line i have unbolt the rubber line and manage to pass the caliper between the wheel and the swingarm in order to raise it as much as possible. Also dont expect a strong rear brake able to lock the rear wheel, if you want more power to the rear you need to drill a bigger hole in the caliper, go see some other thread running on there .
For my part i'll wait after the track day to see if i want a stronger rear brake.:thumbup

There is only 1 mod that fixes the problem in my opinion. And you get some bling while your at it

http://www.satoracing.com/rearsetsrsv2.htm

These rearsets relocate the rear master cylinder...with this new location you shouldn't experience the problem any longer.

Robbymoto also offers some but the Sato's are the bees knees.