can anyone help me with how to take them apart and clean them? thanks

check it out (http://www.off-road.com/snowmobile/info/howto/exhaustvalves/clean/katexhaustvalves.htm)

Good write-up, however I found the easiest way to clean is to use a brass wire wheel on a drill or dremel tool. The valves are hardened, you don't have to worry about marking or damaging them. They will clean up perfect in 5 minutes like this and no chemicals.

Before you clean the power valves - run some ring free from Yamalube through your gas tank, it does a really good job of breaking down carbon without the harsh chemicals or wire wheels, another good way is using Amsoil's power foam spray into carbs, run engine (under 5500 rpm's) until smoke is along gone (it will smoke) then spray into spark plug holes let it sit over nite and get at.
Both products work really good if given time for it to do its job.

$1.25 a can carb cleaner from Auto Zone did wonders for me