Beiträge von Hadder

When you take your motorcycles to change the spring, I recommend asking the technician to check the condition of the pump cylinder, that it is not scratched or with signs of friction, because when changing only the spring, the only thing that will happen is that the force of the spring will make the piston return completely but the friction between the piston and the pump cylinder will persist and you will have in the future will be oil bleeding in the pump on the side where you push the lever, and that expense will be borne by you maybe when the motorcycle's warranty time is over.

In my case they will change the pump, piston and spring, right now I am waiting for the parts to arrive.

Master Cylinder 1.jpeg

Now I am anxious to see if they redesigned the piston or what change they made to it or to their oring, I think that is the origin of the problem, because I would not consider that they only change the piston for another equal or put a spring with more force, I would not believe that that is the solution.

Zitat von dd7

Hadder welcome and thank you for your contribution; good job

I'd like to suggest - if it's an option for you - that you write in english. I assume it will be acceptable for the majority here. If we start to mix 3 languages in one thread it's gonna be a mess ;-)

But back to the actual issue: on my bike I've experienced the brake lever to become harder by itself; hovever, I had this phenomenon so rarely that initially I thought there was the ABS module doing something in the background (it happened especially during riding on very bad surfaces, causing a lot of heavy vibration to the motorcycle). Then, reading through the forums I realized, that it was actually the same issue that has led on other bikes to brake disc discoloration / front wheel blocking / sudden braking power loss. I never came across the idea to open the master brake pump as you did. Firstly, because the bike has still warranty and secondly, I am not sure whether I'd be able to bleed the system properly then (if you look up the workshop manual it says to connect the KTM diagnostic computer to carry out brake system bleeding). Did you bleed the brakes then by yourself? I assume after you've found what the damage you didn't... Nevermind, I really appreciate you have posted the pics. Very interesting!

Cheers,

Dawid

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Thnks Dawid, my motorcycle started with that problem of free movement in the lever on occasions close to 3000 km and whenever I took it to the workshop they told me that the problem was air in the system and they bleed it. Then at 15,000 km one day on a trip the lever began with that free movement, I began to believe that it was normal, because on several occasions it had happened to me and also to several of my friends in their KTM 790, but for a moment to another the lever hardened and the wheel began to brake until it was completely blocked on the road, I went back to the workshop and they checked everything (I don't know if they disassembled the entire brake system or only superficially checked) but they did not find anything strange, only I was told that the system had air.

After that revision it worked well until around 20,000 km where the free movement of the lever returned very exporadically until now, which has 26,000 km, but every time I felt that strange movement in the lever I myself would bleed the system as is normally done at home since it is not necessary to connect the bike to the KTM diagnostic computer if the abs module is working well, and I did not want to go to the workshop to be told that it was just a matter of bleeding it.

But 2 weeks ago it happened again that the wheel stopped and was blocked again in the middle of the road.

This time I decided to check the braking system myself, so I started to disassemble everything until I found that friction problem in the pump, I spoke to the KTM workshop and I took the bike so that they could see the cause of that failure and can now give me a definitive solution.

I didn't dare to disassemble everything either because the bike is still under warranty, but seeing that my life could be in danger and that they didn't find the problem or a definitive solution every time I went, that's why I decided to do it myself.

Zitat von sigi1995

hello hadder, i think this is spanisch, but nearly nobody of us speak spanisch. why you don't use Google translater?

this Problem will be an official call back during the next days.

Hi Sigi, thanks for your notice.

Hallo meine Herren, ich bin neu im Forum und spreche Spanisch. Dann werde ich einen Übersetzer verwenden, um mit Ihnen zu kommunizieren. Vergib mir, wenn du mich nicht sehr gut verstehst.

Ich habe ein KTM 790 Adventure Year 2019, das bereits 26.000 km hat. Dieses 3000 km lange Motorrad stellte dieses Problem mit dem Druckverlust und dem Spiel im Hebel dar. Immer wenn ich es in die Werkstatt brachte, sagten sie mir, dass Luft im System sei, aber vor einigen Tagen kam es vor, dass dieses Motorrad das Rad unerwartet bremste und blockiert, ohne das Motorrad irgendwohin bewegen zu können, da es langsam ist, gab es nichts zu bereuen.

Aus diesem Grund habe ich die Pumpe selbst zerlegt, um festzustellen, was diesen Vorfall verursacht hat, und festgestellt, dass zwischen dem Kolben und der Pumpe Reibung besteht. Es sieht so aus, als ob der Kolben aus irgendeinem Grund gekreuzt und verriegelt wurde. Ich denke, die Lösung besteht nicht nur darin, die Feder zu wechseln, und ich denke, der Kolben hat gegen Ende ein Problem mit seinen Abmessungen. Es scheint mir, dass der hintere Zylinder einen kleineren Durchmesser haben sollte, damit er nicht am Pumpenzylinder reibt.

Diese Woche ist mein Fahrrad in der KTM-Werkstatt, damit sie mir eine endgültige Lösung geben können, da es sehr gefährlich ist.

Ich werde einige Fotos anhängen, damit Sie das Problem sehen können.

Wie Sie in diesem Link sehen können, war es die Bewegung des Hebels, als er zeitweise und besonders auf langen Fahrten das Problem hatte.

https://streamable.com/jsx48a

Piston 1.jpgPiston.jpgMaster Cylinder 1.jpeg