Clutch fluid leak?

[Garrydymond]

About 2 years ago I had to top up my clutch fluid. I had been riding in very hot conditions and thought it might have evaporated as there appeared to be no leaks. I bleed the system when I finished the trip 3 months and about 15,000 miles later. Today I had a low level again and bleed and refilled the master cylinder.There is no visible leak anywhere and the master cylinder cap is fitted correctly.
i am wondering if the slave cylinder seal is leaking but the fluid is staying inside the housing. Has anyone had this problem. The bike has 127,000 kms. The seal is not listed in the parts diagram and you have to buy the complete slave cylinder.
does anyone know the size of the seal?
Any other suggestions?

 

[gunslinger_006]

About 2 years ago I had to top up my clutch fluid. I had been riding in very hot conditions and thought it might have evaporated as there appeared to be no leaks. I bleed the system when I got finished the trip 3 months and about 15,000 miles later. I now had a low level again and bleed and refilled the master cylinder.There is no visible leak anywhere and the master cylinder cap is fitted correctly.
i am wondering if the slave cylinder seal is leaking but the fluid is staying inside the housing. Has anyone had this problem. The bike has 127,000 kms. The seal is not listed in the parts diagram and you have to buy the complete slave cylinder.
does anyone know the size of the seal?
Any other suggestions?

I have not had this but your theory is good unless the fluid is leaking from the bleed screw.

There is a german company making an aftermarket slave cylinder, its $$$ but it may be a good choice for oem replacement.


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[Squibb]

Sounds like the slave is leaking slightly, probably weeping down the pushrod if you can see nothing externally.

A common problem in my previous KTM990 days, but not with Yamaha.

 

[bimota]

I have not had this but your theory is good unless the fluid is leaking from the bleed screw.

There is a german company making an aftermarket slave cylinder, its $$$ but it may be a good choice for oem replacement.


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got one

 

[PhilPhilippines]

got one
View attachment 79583

I do love quality engineering. Looks to be from the same overengineered dept as Tabasco's bash plate, in that it will outlast an everlasting bike...

 

[gunslinger_006]

I do love quality engineering. Looks to be from the same overengineered dept as Tabasco's bash plate, in that it will outlast an everlasting bike...

As the proud owner of one of those plates, i can testify that future civilizations will find little of the fact we existed, except for old nokia brick phones and Tabascos bash plates.


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[PhilPhilippines]

As the proud owner of one of those plates, i can testify that future civilizations will find little of the fact we existed, except for old nokia brick phones and Tabascos bash plates.


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LOL
Nokia 3310... 999 ways to dissipate impact


Tabasco Bash Plate.....**hol' ma beer........**

 

[Garrydymond]

After pulling the slave cylinder off it looks like it has a very slight leak. I will check tomorrow if Yamaha Mexico has it in stock. If not I will get one shipped from the US.
It is a bummer you can’t buy a seal kit and have to buy the complete piece.
I am not using the bike much now because of Covid but think it will be ok to use until I get the new part.