How to improve my front brake?

Technical Small Block V Twins (not new V7s)
1

Hi,
Nearly got caught out by 1984 V50 front disc brake. It passed the mot but you have to pull the lever hard. Anyone tried different pads or master cylinder. Nothing is seized and the pads are 2000m bedded in. The pads are from Gutsibits.
Any suggestions?

2

Are you still on a linked system? If so, a smaller master cylinder helps. I’ll have a look in Guzziology later to find the recommended size, but also get your brain trained to use the foot pedal as the main brake…

3

Hi,
Yes it’s still linked. Brain training, not sure if I know where that is!
I’ll be interested in what Guzziology has to say.
S

4

Didnt one of the V50s have it cable operated to the master cylinder …or am I imagining it…

5

They did Kate, but an 84 V50 is probably a mark 3 and I think they had a conventional handlebar mounted master cylinder.
Braided brake lines will help get more of the pressure into the caliper if not already fitted.
If you have never had the calier apart it would be worthwhile checking the seals, and see if it has rusty old steel pistons or the better teflon coated ones.

6

I’ve fitted an 11mm master cylinder from a Honda Silverwing FJS600. I haven’t yet tried it in action but the lever feel is much better.Also fitted EBC organic pads all round as the PO had fitted a weird mixture of sintered and organics.

I made a list of Honda master cylinders that had 11mm bore and came up with this:

CB500
CBR125
FES125 Pantheon
FES250 Foresight
FJS600 Silverwing
NTV650 Revere
NX650 Dominator
Transalp 600
CB250 N/T/W/Y (Not Super Dream)
VF750
VT125 Shadow
VT600
XL125 Varadero
XL600
FJS400 Silverwing

but don’t take it as gospel as different years may have different systems…

I got my cylinder from ebay for around £30 - in very nice condition.

7

The linked set up on these is excellent. If you can get used to using the pedal more it is mostly all you need - just like a car really, if you think about it.

It was the mk II that had the ghastly cable/hydraulic hybrid. I don’t think it is just the cable that makes that bad, I think the piston diameters are probably not right in the hydraulics as well.

I swapped mine out for a big twin master cylinder on the bars - which also has a piston too big for the caliper. But with the softest pads I can get and some of the anvil filed off the lever so it bites nearer the bars it is just about OK … accepting that I barely use it. See first sentence.

8

I accept that if a Guzzi is your only bike then the linked system is excellent. But for those of us with others - especially where the rear brake lever is on the opposite side - it’s tricky to keep rewiring your brain especially in situations where a rapid response is required.

I’ve discovered that changing into top on the Arrow (or most of the other bikes I’ve had) doesn’t do a lot for retardation.

Mind you on the Arrow it doesn’t go much faster either…

9

The Guzzi is the first bike for many years with a r/h (foot) brake. If you have time the linked system is great, especially in the bad weather. Mine is a mk 3, so handlebar reservoir. I need the front to be a lot better, change of pad material, or master cylinder size. Interested in the 11mm cylinder.

10

Guzziology says either 11mm or 10mm give a useful improvement in ratio between master cylinder and caliper, therefore better feel. I put an 11mm on my Spada and it is much better, although I only use the front as a secondary brake. The linked pedal is adequate for most riding.
If you want a new master cylinder, this is what I found:

https://www.stein-dinse.biz/Ducati/Brake-system/Front-master-cylinder/Front-master-cylinder-PS-11-with-reservoir-black-p::7630.html#prettyPhoto

90 euro brand-new from Stein Dinse. If you need a mirror mount there is another version.

11

Hi,
Yes the linked system is good for most circumstances… However, as I mentioned in my first post I wanted a better front brake. Not for the first time someone decided to enter a roundabout from my right faster than the speed limit, looked right but not where they were going. I was only going 15mph but hence the need for a instant front brake!
Thanks to all for your help. The bike is coming off the road shortly to cure the numerous false neutrals, so time to sort the brakes then.
Steve.

12

I see Gutsibits do an 11mm master cylinder.
10mm seems difficult to get, so will try the 11
S

13

Ferodo or EBC brake pads? The stock Brembo pads are generally naff and have been for several years now.

I’m a bit surprised tho, I mean at it’s best the braking performance should be what was considered good or at least adequate in 1984, but the MOT tester didn’t take that into account? Or not understand the lever only works one front disc?

\

14

Well, as noted mine is still not fantastic with the ‘big piston’ conversion that I did. When I recommissioned my pals V50 a couple of years back I was still shocked at just how bad the std cable/hydraulic set up is. When I moved house many years ago, first time out at a new MOT station mine (still std then) failed on front brake. I found someone else to do my MOTs.

15

Hi,
Mine are EBC .
What’s a “big piston” conversion? Does it refer to master cylinder?

16

I’ve clipped the quote - hopefully I haven’t ballsed it.

What I mean is - I simply swapped out the std hybrid cable/hydraulic system for a master cylinder and lever from one of the big twins and that sits on the handlebars. This really has too big a piston diameter for the smaller small block calipers. It shifts too much fluid and so leads to a wooden feel and requires quite a lot of applied pressure at the lever. It really needs a master with a smaller cylinder diameter - I think we’re suggesting 11 or 12 mm will give better results.

17

No, it’s good. Makes sense anyway.
Couldn’t make sense of the logic to increase the m/c size for a better brake!
Mines a my 3 so no cable. Need to save the pennies for a 11mm set up.
Thanks.

18

I’m not an expert but Guzziology says that the same master cylinder is used on both big-block and small-block. 12.7mm I think. I certainly found the front brake on my Monza very wooden, but was good enough for an MOT. Small hands don’t help either.

19

Warning - left field question;

So if you have a fully bled and working system, and then you swap out one master cylinder at the handlebars for another, you’ve now introduced air at the top. If you then top the reservoir up and leave, given that with the lever right back the system is effectively open shouldn’t all of the air bubble up and out through the reservoir, so no additional bleeding required?

Seems much simpler than forcing any air down to the caliper and then out through the bleed nipples there.

20

Hi,
If you prime the new cylinder there shouldn’t be a need to bleed the system. However :question: as there is only the one right hand caliper I’d be tempted to bleed the complete system for peace of mind.