I don't have a UCE bike in front of me here, because our test mule is up in NJ with Chumma.
However, the engine breather hose should have a one-way valve on it, such as a duckbill, or a fast acting PCV or brake-booster valve, or a KrankVent breather valve.
Even though the UCE has a wet sump and an included transmission housing that gives it more internal crankcase volume, the breather is still important to keep low pressure inside the crankcase.
So, if you trace that engine breather hose system, and see whatever it is attached to, there should be some kind of fast-acting one-way valve somewhere in that route. If there is nothing like that on the breather hose, then you will be pumping air in and out of the crankcase through that hose, which uselessly wastes power, impedes ring sealing, and may even cause some unnecessary oil leaks.