Crankcase vent size?

[fj1289]

Tried searching for this - what is the size of he crankcase vent?  Will 1/2" hose fit?  Or does it need 5/8"? 

Forgot to look at it before heading to work -- nearest parts place from home is 20 minutes, so want to get it on way home from work today. Redoing the breather and catch bottle arrangement on the dragbike and want to pick up some transmission cooler line to run the new setup.

Anyone else have troubles finding info like this using the search engine?  That is the only thing I don't like about this board. Using most search engines I can pretty quickly find what I need - but this one either pulls up no results or a BUNCH of unrelated posts...

Thanks!

Chris W