FAding 520 EXC Clutch

[Dominicano]

Hi!. After replacing slave clutch cylinder (The one close to countershaft sprocket)after broken chain hit it i have been having problems with the cluch. Right after the system is bled it works fine. After several minutes on the woods it will not work at all. It acts as if it has no fluid on the system. After 20 to 30 pump strokes iit starts to work really close to the handlebar, eventually regains pressure and works fine for a mile or so then it goes away. Maybe it happens when hot and after it cool it comes back?.

I have tryed ATF, Power Steering Fluid, Hidraulic oil used on european cars on Self Leveling Suspensions, SAE 30 to no avail.

I also replaced master cylinder internals from another one.

Is the oil sold by KTM really different from all available oils.

 

[V-man]

You need to use mineral oil only for the clutch. By using the oils you listed damage has been done to the internals. Had a friend do the same thing!

 

[TM-Frank]

Your problem hast nothing to do with the fluids you have tried.
When you say it works as if there's no fluid in there, do you mean the clutch doesn't engage? You pull the lever to the bar and the bike is still moving forward?
Check if the steel plates are warped. My riding buddy had this twice on his 520 with the same symptons as described above.

Frank

 

[Dominicano]

Thanks for your kind replys.

When i say that the clutch acts as if there is no fluid in the system is that the lever is completely loose with no resistance or pressure at all.

This symptom reminds me of a worn out brake pump in a car.

After it cools down a little and you pump it several times it start to get some pressure.

 

[marcusgunby]

You have got or are getting air into the system-try a new o ring on the slave cylinder and check all hose connections.

 

[ml36]

tm-frank is right. none of the fluids you have tried will attack the system. you have got an air bubble in there somewhere. these things are a pita to bleed correctly. i know quite a few poeple that have had this same exact problem.

 

[colorado-high]

You definitly have some air in the system. KTM has a syringe the attaches to the bleed nipple on the slave cylinder to draw the fluid thru the system. You can go to a drug store and buy on there. Just attach a hose from the syringe to the nipple. Also I use Johnson & Johnson baby oil in my clutch. It is pure mineral oil with scent added.It make for a very light pull on the lever.