Which lever/master ass'y to swap onto uh, another Italian bike...

[Mr Earl]

So now the garage houses two Italian beauties, my 2003 M800 and a 2000.5 Aprilia RSV Mille R.  The RSV-R is an awesome bike, with one exception:  the front brake.  The components, from the top of the SS braided line to the pads, is identical to the Monster, 4-piston, 2-pad Brembos.  But the Monster's brake is just way firmer, with lots more stopping power.  I use one finger to stop the Monster, the Ape needs 2.  Yesterday I replaced the pads (stock Brembos in good shape) with EBC HH sintered, fully flushed the two lines and topped off with Dot 4 fluid.  Slight improvement.

I'm thinking the lever/master assembly is the only difference between the 2 bikes' brake setups, so why not replace the stock Aprilia setup with...  well, with what?  The Monster is a coffin master setup, and the Ape's is a pee cup.  Any thoughts or suggestions?   

[Howie]

Masters have the same size bore?

[Mr Earl]

Masters have the same size bore?

Don't know.  I suspect they are different due to the different characteristics of the two.

[Mr Earl]

Looking at ebay auctions, the Aprilia setup appears identical to the 748.  Which have great brakes, yes?  Maybe the brake unit itself isn't the problem...

[Mr Earl]

Any help?  I just rode the Monster and almost did a stoppie after getting used to the Aprilia's lever pull.  Is there a likely cause for the heavy lever pull on the Aprilia that is related to the lever/master assembly?

[stopintime]

I don't know what's up with the Aprilia master, but if you like the Monster master - get one...

YoYoDyne sell the 16mm coffin for ~$120 AND will be able to confirm fit.

[Howie]

Before buying anything confirm all the pistons in the caliper move freely.  What was the wear like on the old pads?  The size of the master on your Aprilia should be on it if it is Brembo.  Look on the bottom.

[Mr Earl]

Thanks for the replies.

The wear on the old pads was even, but one pad showed slightly more wear than the other on each side.

When I replaced the pads and pushed the pistons back into the calipers, I did it by hand (rather than a C-clamp or what-have-you) and they pushed in with resistance, but smoothly and steadily.  Does that confirm their function or should I pull the calipers and pads and then squeeze the lever and see what happens?

Thanks for the tip on the Yoyodyne setup. 

[Howie]

Minimal wear difference is normal, excessive indicates sticking pistons with a fixed caliper.  Before leaping into the calipers do keep in mind your brand new HH pads are not bedded in yet.  Particularly with used rotors this can take quite a bit of mileage.  If you can, follow this procedure
http://www.braketech.com/index.php?option=com_content&view=article&id=54:racing-brake-pad--bed-in-procedures&catid=17:tech-talk&Itemid=69

Living in Da Bronks this is very difficult for me.  Moderate braking (not too hard, not too light) for about 200 miles usually works well enough for me.  Needles to say, if you need to brake hard to avoid an accident, do it!  Light braking with new pads tends to create overheating at whatever contact points you have, leading to squeal and diminished performance.

[Mr Earl]

Thanks, Howie.  I'm starting to believe that this is a bleeding issue.  Although I pulled fresh fluid through the front brake system, I didn't do a traditional bleed on the calipers or the master.  I've since bled the master, and braking improved significantly.  Not to my Monster's level, but a lot better, enough to be confident riding it.  So tomorrow a thorough bleed of both calipers and the master again (any preference for what order?) and then the bedding-in exercise.  Then we'll see.

BTW, you all may know this already, but Brembo apparently does not sell rebuild/recondition kits for these calipers.  I have learned that some are available through KTM, however.

[Howie]

Calipers first, then master, keepnig the master as close to level as possible.  Then tie the lever to the grip (applied position) over night.  Still no good?  There are other tricks, post back.  Also, squeeze the lever slowly.