Sherco radiator cap and master cyclinder.

Hi guys, I recently got my first trials bike a 02' Sherco 2.9 and have a few questions about it! Frist off is that needs a new front brake lever and potentaily a new master cylinder (the reach adjuster is broken) .  Has anyone had any luck switching master cylinders from a Japanese motocross bike.  If there was one that fit the hose and had the same piston size I think It would be easier to get repalcement levers.  Also my radiator cap leaks coolant out the vent hose as I'm riding (the fan is working), have any Ideas?  Where can I get a new cap?
Thanks,
Mitch

I don't think you need to be concerned about getting replacement parts.  Pretty much everything should be available here http://www.rypusa.com/

As for the coolant out of the vent hose... it probably was slightly overfilled, and the first couple times it gets hot it will run out the vent hose.