I am rebuilding the clutch master cylinder using a service pack. Between the reservoir and the cylinder bore there are two small holes but only one is open, the other (smaller) one is blocked - not sure if with hardened muck or deliberately. My question is should it be like that or should they both be open?

Thanks

Hi Redmidget,

The other hole (very tiny) should also be open. This is to make sure that when the bike warms up and the engine parts expand that the fluid in the clutch system can escape. If the hole is clogged/plugged you might see that the clutch is starting to operate itself when the engine warms up...

Hope this helps.

Cheers,
Bas

Thanks

As you were entering this I found a really useful website about brake cylinders. Fortunately you told me the hole is very small because the diagrams on the web don't make that clear and I would probably have enlarged it.

Chris

No problem, glad you found your information.

Had this problem on a friends bike (not a Ducati though), which would cause the clutch to slip under load when warm. Not very nice!

Cheers,
Bas