That's air in the system, not fluid degradation..... the problem is "how is it getting there?" and "how do you get it all out easily?"...questions not answered.My rear brakes fails, without any use. Unfortunately we are talking days/weeks, rather than months/years. Not particularly hot or humid here though.
It's not a matter of time. It's more a matter of use and distance ridden.
My bike has about 7200 miles. Bought new Jan 2018.AND time....moisture absorbed while just sitting. Especially in hot and humid environments.
During my stint working for Honda (AHM) we had a similar problem that involved Accord models from 2003 to 2008.@Teeps , I am convinced the ABS system is the cause of so much aggravation on the MV 3 cylinder bike rear brakes, although I can't explain how since many other brands and bikes have a similar system (components and design), and the front brakes use the same pump/module with some long convoluted routing hoses.
Your eliminating it with good result seems to uphold this suspicion.
I wonder if any of the 4 cylinder ABS bikes have had similar issues??
Odd that MV reputedly doesn't have ABS test cycles in the diagnostic software. Most manufacturers do.
I think I'll chat with my local MV dealer about this and get his insight.
At Honda I was not a subject matter expert of ABS (systems.)@Teeps Just not sure how air gets in there. I have disassembled (destructive unfortunately, no other way) several ABS modules. There ain't a lot to it... Regardless, air is getting in somewhere and the ABS unit is the only place I can imagine without fluid also getting out.
Here are a few pages from a Suzuki manual that have great diagrams of what is in that module and how it works. Not an MV manual, but all ABS system used on bikes work in similar ways.
On the ABS PDF diagram the "Solenoid Valve OUT" are the ones that help prevent the pulsing of the lever during operation present in early ABS systems. The reservoirs act like shock absorbers.