V65 - delinking brakes, master cylinder choices ?

[chrisk]

Hi y'all,

I'm going to delink my v65 brakes, but am assuming that the front master cylinder won't be man enough to drive the two front discs. Is there a popular choice or suggestion for a replacement front mcyl ?

I'm assuming the rear will be okay, probably too powerful for the rear disc alone, but I guess that's okay ?

Thanks

[Hymes Inc.]

We did this to mine. I will have to talk to dad (wymple) about which master cylinder he ordered for the front. The rear works normal.

[Dukedesmo]

I did this on my Lemans, not sure if they use the same calipers or not? but I used a Brembo 15RCS on the front which works perfectly, it has an 18/20 switchable ratio and I'm on the 20 for a shorter pull otherwise it gets close to the bars and as I'm a two-finger braker, will trap my other fingers.

Even if you don't want the RCS, I would suggest the 15mm master is correct as the rear master was a 15 to operate 2 calipers, assuming your bike has a 15mm rear? and as  the rear caliper is the same as a front on the LM, then keeping the same overall size should be the way to go.

I also replaced the hoses with braided and overhauled the calipers with new alloy pistons (the chrome pistons were corroded and sticky) and seals.

As for the rear I fitted a smaller 13mm master because the 15 (for rear plus one front) would be too big.

[chrisk]

Hi, I'm guessing the calipers and discs are different,  the v65 has 260m discs but I think it's the Caliper piston size that is used to define mcyl diameter.
I think the rear is 15mm but I'll check.
Did you run 2 lines from the front mcyl or 1 and put a junction in?

[Stevex]

I was going to chip in with my MC sizes after I de linked my LM2, but I see the front calipers are F05s on the V65 as opposed to F08s on the LM.

[Dukedesmo]

Did you run 2 lines from the front mcyl or 1 and put a junction in?

I ran 2 lines from the master as it's both an easier and (IMO) better solution.

I think they're the F08 calipers on mine which are only 2 piston but the pistons are quite large, 15mm master is perfect for the 2 calipers/4 pistons.

Here's a pic of the master cyl;



One good thing about RCS master cylinders is that they are available in several different sizes so you should find one to fit most caliper types/sizes.

[chrisk]

thanks and nice job

[Orange Guzzi]

There is a web sight called Vintage Brakes.  There is a ratio chart and a description on how brakes should work.  Very helpful.  You will need to replace the rear master cylinder also.  The oem will be to large in diameter to work the small rear brake caliper 

[Antietam Classic Cycle]

There is a web sight called Vintage Brakes.  There is a ratio chart and a description on how brakes should work.  Very helpful.  You will need to replace the rear master cylinder also.  The oem will be to large in diameter to work the small rear brake caliper

http://vintagebrake.com/mastercylinder.htm

[wrbix]

Again, Guzziology has a table/description/explanation of MC to SC match ups particularly referrable o Guzzis

[Devildog]

What is the reason to change it? The linked brakes was one of the features I liked about the bike, and it seems to brake effectively. In a panic stop wouldn't there be less chance of the back tire locking up and the back end sliding out?

[Hymes Inc.]

I used one line from the master cylinder to a splitter I made mounted under the headlight where the plastic Motto Guzzi emblem piece was. I changed mine mostly because I was minimizing clutter and didn't want to run a line from rear to front.

[Dukedesmo]

What is the reason to change it? The linked brakes was one of the features I liked about the bike, and it seems to brake effectively. In a panic stop wouldn't there be less chance of the back tire locking up and the back end sliding out?

I'm not a big rear brake user, years of riding bikes with little rear end braking (Ducati) have made me that way so it doesn't feel instinctive to me to use the rear.

But the main reason I did it was that I couldn't get used to having virtually no stopping power from the brake lever - 1 caliper is just not enough power, 2 are nowhere near as strong as my other bikes (4-pot Radial calipers) but are acceptable, with a bit more forward thinking.

The concept of linking is good but I don't want to compromise on front braking, as for the benefit of both working together I can still use both brakes together if I choose to...

[Orange Guzzi]

I'm not a big rear brake user, years of riding bikes with little rear end braking (Ducati) have made me that way so it doesn't feel instinctive to me to use the rear.

But the main reason I did it was that I couldn't get used to having virtually no stopping power from the brake lever - 1 caliper is just not enough power, 2 are nowhere near as strong as my other bikes (4-pot Radial calipers) but are acceptable, with a bit more forward thinking.

The concept of linking is good but I don't want to compromise on front braking, as for the benefit of both working together I can still use both brakes together if I choose to...

On the two Guzzi's I delinked, I tested the brakes by removing the front linked caliper from the fork stanchion.  Then went for a ride.  I was surprised that the rear brake has very very little stopping ability.  When I reconnected the front and removed the back for a test ride, the rear pedal braking compared to the front lever braking was not close.  The rear pedal offered very little stopping ability at the front wheel.  When I separated the two systems, I use organic pads on the back and HH pads of the front.  The bikes stopped much better and with better control. 

Testing is easy, remove a caliper, stick a paint stirring stick between the pads and support the caliper with a bungee cord.  Go for a ride around the neighborhood.

If you have the fat bars with the 7/8 ends, you will need to by the correct front master cylinder.  I will have more offset from the bar clamp and the reservoir.  Brembo makes them.  Front calipers have different offsets unless you use one with a urine specimen cup.