Better master cylinder?

[m in sc]

if you are talking about this one:

https://www.mikesxs.net/yamaha-xs650-76-type-single-master-cylinder-oem-366-25850-02-00-366-25850-02-00.html

the threads wont do anything to seal. they need to breathe to allow the bellows to move to displace the fluid. however, if its leaking at the cap, take off and check flatness of the sealing surface on the main body. if its uneven (bet it is). flatten on peice of glass and emery cloth. 

[RDryan]

if you are talking about this one:

https://www.mikesxs.net/yamaha-xs650-76-type-single-master-cylinder-oem-366-25850-02-00-366-25850-02-00.html

the threads wont do anything to seal. they need to breathe to allow the bellows to move to displace the fluid. however, if its leaking at the cap, take off and check flatness of the sealing surface on the main body. if its uneven (bet it is). flatten on peice of glass and emery cloth. 

Hmmm, that makes sense. I'll have to check for flatness and try that. I really like the stock look of it and hate to replace it for such a silly reason plus I'm already into $ it. To spend more money on it seems silly to me.