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Discussion Starter · #201 ·
I love Physics.

So I recently went through this with my new(ish) 2021 Superveloce. Brake was completely fine for a few months, thought I had dodged a bullet, then it got all mushy. No amount of "regular" bleeding seemed to help. I'd maybe get a tiny bit of pressure that would then disappear right away.

Reading through here I noticed three things people seem to say help:
1) Remove and invert rear caliper, then bleed
2) Bleed from the ABS pump
3) Relocate the fluid reservoir to above the ABS pump.

I decided to try all three, since I was getting ready for a 600 mile trip and didn't have time to try each one alone.

I relocated the reservoir, then bled from the ABS, then bled the inverted caliper.

So Far, the brake is hard as a rock and works about as well as a rear brake on a sportbike could work.

It does make my inner engineer tingle knowing that gravity is helping the reservoir apply positive pressure on the whole system while it sits there.....
Just get a length of regular clear brake line. Available at almost any bike shop.
 

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Reservoir hose is under no pressure....clear tubing that is oil resistant sourced from the local hardware store will work.
 

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2021 Superveloce 800, 2002 RC51, 2008 E90 M3, 1974 Crosle 32F, some SUVs
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I read on this thread enough times that dealers stopped covering, that I didn't even ask them here in the US... I just fixed it.
 

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2021 Superveloce 800, 2002 RC51, 2008 E90 M3, 1974 Crosle 32F, some SUVs
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Reservoir hose is under no pressure....clear tubing that is oil resistant sourced from the local hardware store will work.
Reservoir hose has at least the pressure created by gravity pulling on the fluid in the reservoir and line....

Like I said, I'm not sure which of the three things I did fixed it, but doing all three made the brake better than it's ever been.

That clear hose gets brittle and nasty after time, in my experience, but yeah, lots of options on the hose.
 

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There are numerous accounts of air in the rear brake system of several models of the 3-Cylinder bikes.
I was perusing a Ducati Forum and ran across the following issue with the crimping on certain ABS equipped Ducati bikes.
As this issue pertains to a very similar, if not the same, equipment on the MV bikes, I thought it might be of interest and might be the actual problem.

View attachment 478843
For air to be able to enter the rear brakeline through that crimp, I'd think that it should also show fluid leaks under pressure??
 

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Turismo Veloce Rosso EAS -20
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I would think that this particular , vulnerable crimp is located at ABS-pump connections, where "negative" pressure is present. Very small "leakage" path is enough for air having extremely low viscosity. While brake fluid has several magnitude higher and pressure is occurring only very short time.
 

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Hello Mv lovers. So after some time, this problem happened to me again.
I must say that I replaced the rear caliper, with a black Brembo one (I will show it with a picture later). It has the hose and bleed valve at the top, this makes maintenance a lot easier, cause I don't have to remove the caliper to make bubbles inside go away.

I replaced all the stock lines between all the calipers to abs module, and between abs module to master cylinders, with aftermarket ones.

I installed bleeding valves in the abs module for the rear brake.

All of these solutions, makes bleeding air bubbles easier. The cause is still a misterio.

I'm looking to my wife bike (cf moto 250nk), that has a Bosh 9 abs module and doesn't have this problem. But the abs module is allmost under the bike...

🤔

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Discussion Starter · #209 ·
... The cause is still a misterio....

I'm looking to my wife bike (cf moto 250nk), that has a Bosh 9 abs module and doesn't have this problem. But the abs module is almost under the bike...

🤔
Physics is the cause. The reservoir needs to be the highest point in the system,
 

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Discussion Starter · #211 ·
@Panchomeneguzi - Um, the front master, and fluid reservoir, is at the highest point on the bike: the right handlebar….
 

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Discussion Starter · #213 ·
It needs to be the reservoir so that it functions as a Head Tank. The highest point in the system.
 

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Yes. And that brake isn't giving any problem...
So it can be the reservoir or the M/C that needs to be higher 😁

Anyway, next thing I will try is installing a reservoir under the seat 👌
If the master cylinder was higher than the abs unit, the reservoir would be as well. The reservoir is always going to be above the master cylinder.
With the master cylinder at your foot, there isn't really anywhere below that to put an abs unit.

It is head pressure from the level in the reservoir being higher than the level in the abs module (and every other part of the system) that you need.
 

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Well, it took me a while to read all of this thread, those that have gone before me appear to have nutted it out.

I bought my Super Veloce in March 2021, I've done 1400 ks and shortly after its first service at 1000 ks, no back brake.
I have 600 metres of dirt from my house to a sealed road and rely on the back brake.
I spoke to a service manager today who was helpful, which between his advice and the findings in this tread has given me a clear path.
a] relocate the reservoir under the pillion seat.
b] bleed the system as per the service bulletin.

Lastly, if this doesn't work then I will bypass the ABS and hone my dirt bike skills.

Just a word of warning regards reservoir pipe, After a bolt and nut resto of a Duc MHR I used a reservoir pipe listed as fit for the purpose, it wasn't fit, it bled out, and it wasn't condensation, next to a newly painted frame.
I tested the whole length I bought over a period of time and it all was the same.
I eventually found the correct pipe in the length I needed.

I'll let you know how it goes.
Cheers Ian. :cool:
 

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All credit to Lowside who came up with this idea,
Did this to my bike about 6 months ago and it works, can actually get the ABS to engage where previously the pedal was too mushy to get enough force despite every manner of bleeding.

Pedal stays hard during layups which we've had plenty of in Sydney due to the covid restrictions.

You need to get EPDM rubber or Tygon 2375 hose to move the reservoir , I used a 15cc Brembo one off ebay.

Re the idea about fluid head etc. I have a KTM SMC R and the ABS unit is way above the rear brake reservoir but it works, gravity must be different in Italy when the bike was assembled.

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Turismo Veloce Rosso EAS -20
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While I got "soft pedal" earlier in the summer, I did proper bleeding only, not even removing caliber from its normal position. Just high-flow bleeding by vacuum bleeder. Those air traps which are accumulated in ABS-unit over the time seems to be removed with fluid when current is high fast enough. Not letting them accumulated then in caliber.

Pedal was getting back to "normal" as it was day one when I received the bike. But, then I have had weight (2.5 ltr oil) hanging on the pedal while not driving. And actually, pedal is getting even "better" over the time. Was driving yesterday in last 3 wks and there were minimal amount of slack before the pedal was engaged.

I would highly recommend this approach other TV owners when there are no chance to get reservoir under the seat or anywhere higher point except bars where it would be looking really "home made" solution. This wouldn't be solution for the bike you are using daily but for me, driving occasionally, it's fine.

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While I got "soft pedal" earlier in the summer, I did proper bleeding only, not even removing caliber from its normal position. Just high-flow bleeding by vacuum bleeder. Those air traps which are accumulated in ABS-unit over the time seems to be removed with fluid when current is high fast enough. Not letting them accumulated then in caliber.

Pedal was getting back to "normal" as it was day one when I received the bike. But, then I have had weight (2.5 ltr oil) hanging on the pedal while not driving. And actually, pedal is getting even "better" over the time. Was driving yesterday in last 3 wks and there were minimal amount of slack before the pedal was engaged.

I would highly recommend this approach other TV owners when there are no chance to get reservoir under the seat or anywhere higher point except bars where it would be looking really "home made" solution. This wouldn't be solution for the bike you are using daily but for me, driving occasionally, it's fine.

View attachment 489258
Thanks for this! Easy to do. Will try it on my Dragster.
 

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Quick update,
I bled the system as per service bulletin on Sunday, the ABS unit had a factory fitted bleed nipple, and the caliper had the bled nipple at the top.
Went for a ride and stood on the rear brake a couple of times, so far [Wednesday] it is still firm.
The rear brake is very average almost wooden, reminds me of the standard front brake on my Norton Commando before I put a Grimeca master on it.
Am I missing something or is this as good as it gets?

Waiting patiently for the new reservoir and brake hose.
 

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Quick update,
I bled the system as per service bulletin on Sunday, the ABS unit had a factory fitted bleed nipple, and the caliper had the bled nipple at the top.
Went for a ride and stood on the rear brake a couple of times, so far [Wednesday] it is still firm.
The rear brake is very average almost wooden, reminds me of the standard front brake on my Norton Commando before I put a Grimeca master on it.
Am I missing something or is this as good as it gets?

Waiting patiently for the new reservoir and brake hose.
Interesting your references of "average" and "wooden" as related to the rear brake of your MV.

The rear brake on my Turismo is way too powerful. Such that I've made entire rides without ever using it to slow.
My previous bike was a Buell Ulysses. That had a wooden feeling rear brake. Guys on the forum would complain about how poor the rear brake was; many sought to increase braking power with different caliper and or master cylinder. For me, it was perfect just like I'd want on a race bike.
 
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