The rulebook states:
"Route all vent, breather, or overflow tubes coming from the engine, transmission, or radiator into either a heatresistant
catch can of at least 350cc capacity, or the air box, which must be sealed to prevent fluid leakage. The
airbox may remain unsealed provided the bike is fitted with a closed belly pan."
If your catch can is 350ml (size of a pop can) it can be located where ever is best on your bike and you do not require a belly pan (keeping in mind that it should be shielded from damage as best as possible in the event of a crash). Your catch can may be mounted above or below the crank case height, but your hoses should be vented unimpeaded directly into the catch can. If you have a belly pan then all vent lines need to routed so that any discharge will flow into the belly pan directly which means ensuring the exit vent point is lower than the bottom of the engine. You don't want fluid all over your motorcycle (especialy the back tire). The key point is to ensure that any venting fluid is captured by the can or belly pan to make sure it doesn't end up on the track surface. Hope this helps.
