[Tamir]

According to Pertzilla's website, OEM parts, these are two "different" kits with a different catalog number and a different price:
For CBR250RA (ABS) - LINK: 45530-471-831 43.20USD Does not include shipping
For CBR250R - LINK: 45530-KVY-911 16.23USD Does not include shipping

According to Wemoto's website, TRK parts, these are two identical kits with the same catalog number and the same price:
TRK (AC7400) ~20USD Does not include shipping
LINK to CBR250RA (ABS)
LINK to CBR250R

In both stores you can find excellent customer service, you can e-mail to them and ask them.

 

[Tamir]

 

[Tamir]

Im from India so shipping is gonna cost me more than the product itself

At Thailand you have an excellent prices too.
Super-Bikers also has an excellent online store:
LINK1 ABS (45530-471-831 26.26USD) Does not include shipping
LINK2 (45530-KVY-911 5.15USD) Does not include shipping

 

[Tamir]

The longer I ride, the more pressure i lose.

no leakage of brake fluid at all

I guess master cylinder is the main culprit.

YES
Sometimes a few activations, pumps, of the brake lever will restore the pressure, but as you apply force on the lever the pressure drops again. Of course you shouldn't drive like that.
In most cases, the cylinder, the bore, was not damaged, and the complete piston kit is replaced, or only the two seals of the piston.

To remove the CIRCLIP (90651-MA5-671) that holds the piston, you need a special tool (e):
Internal Snap Ring Plier with a narrow and long nose.

 

[Tamir]

Cahuna & BG covered the issue very nicely.
If I understood, the thread opener does not have a problem with brake fluid leakage.
I'm not so sure about "easy job".
According to the manufacturer's instructions:
Handling the brake system requires a mechanical skill.
The brake system is a safety system and there you have to be even more careful.

If I understood correctly, the thread opener buys parts himself and does the work himself, and has a mechanic that he consults with. But maybe I misunderstood?

It is possible the wrong DOT brake fluid is eating away at the rubber seals.

As long as it is correct DOT brake fluid, it will not cause any damage to the rubbers.
The manufacturer sets the standard for our CBR250R(2011-2013) brake fluid to: DOT3 or DOT4
It is forbidden to mix different types, and must be replaced every two years.

Brake fluid absorb moisture to it, so failure to replace it on time can destroy(by rust) the metal and aluminum parts,
and destroy seals that wear out because they friction on the damaged metal surfaces.

Updating
Moisture in the brake fluid is also dangerous because it lowers the boiling temperature, (when the fluid boils it turns into a gas, which causes a complete failure of the braking system)

 

[Tamir]

Yes i buy the parts myself but installation done by a professional. I do consult him and buys the part he ask me to.
A pay close attention to everything he tells me I question him and look out for what he's doing.

Hi
"i buy the parts myself but installation done by a professional"
I don't usually criticize other mechanics, it's unfair and unethical.
Just be aware that your combination that you are telling us about does not give you effective results,
and even puts you at great risk.
You need to think on other combination method.

No one has any intention of saving money and putting themselves in danger because they saved money.

You cannot continue to ride your motorcycle when the brake system is not working

 

[Tamir]

Seems like you solved your problem.

You are not accurate.
He took the fuse out, and he claims it stopped the leaver from sinking.
So maybe the problem is: DELAY VALVE 46300-MFG-D21 (NEW for ~107$)???
So there is no point in rushing to announce that either.
LINK to PARTZILLA

If the suspicion falls on the ABS system, a systematic diagnosis should be made for that system.
Of course you will also start replacing parts. Both methods are good.

I do not have experience with ABS devices

I do not have either.
These ABS systems do not add safety to motorcyclists, and I am not the only one who claims this.
When it comes to maintaining an old bike,
maintaining the normal braking systems without ABS is much simpler.
I can like the idea of removing the fuse, if it really solves the problem.
On the other hand,
if there is already an ABS system and it is not working, I would make an effort to fix it,
that is part of the fun, a part of the hobby (DIY).
A hobby costs money and does not save money.
And the reward is the pleasure of a successful repair.

 

[Tamir]

This video describes a condition that causes the lever to sink to the handle and not work

Yes, when the Dump Valve remaining open to LPA.

The explanation in the video is excellent!
Now I have to compare it to the scheme of the system in our Honda and try to understand what is similar and what is different...at the end I will accidentally understand how our ABS system works

 

[Tamir]

Update
I looked at P.15-12 and P.16-3, and I couldn't understand what was inside the "black" boxes of the various components