my brother has just bought a 16 ice hell. we was swapping the master cyclinder covers over to some nice red csp ones earlier and noticed the clutch master cyclinder was completely empty of fluid.

which seems weird as it worked when I test rode it a few days ago. 

I'm presuming it will need bleeding rather than just topping up as its completely empty up top. and how are these bled? there isn't a nipple near the casing where the hose is like on my beta. 

thanks

Just top it up, turn bars to right full lock and pump the lever. If the fluid starts to drop either the hose is damaged or loose or the slave cylinder seals have failed. 

46 minutes ago, baldilocks said:

Just top it up, turn bars to right full lock and pump the lever. If the fluid starts to drop either the hose is damaged or loose or the slave cylinder seals have failed. 

Even if the master cylinder is completely empty I thought it would have had a air in by now 

It's how I bleed them when I have to fit a hose so will work. With the bars on right hand lock the clutch master cylinder is at its highest point. Back the adjustment off on the lever so there free play in the system then pumping the lever will cause any bubbles to rise. No need for a bleed nipper. 

Others may disagree but it's always worked for me and it'll take5 mins if everything is ok so you don't have a lot to lose.

The resevior is only a resevior. Aside from keeping the fluid in the active system filled it’s pretty much out of the circuit once the lever is pulled. The question is do you have a leak somewhere that caused the fluid to need to be replenished by the resevior. First fill the resevior. Then do the simple test of pulling in the clutch and holding it to see if the clutch stays disengaged and the lever pull doesn’t change. If it does you have a leak and it’s time to go hunting. Check all the connection points (banjo bolts) for any sign of leaking fluid. The most common place for leaks and the one that can’t be seen is around the slave cylinder. If that’s leaking you need a rebuild kit.

All systems use some fluid as even the microscopic surface of the best hydraulics weep some fluid. So there is still the possibility that this is just a normal loss of fluid or unfilled system and you can just fill it and forget about it.