Originally Posted by
TPEHAK
You do need catch can when you'r doing breather reroute for the same reason you need fuses in electric circuit. In most cases you might thing you do not need fuses because of it works without them, but when something happening it can burn your circuit and electrical components without fuse. Same thing for catch can, you might think system works without catch can, but when something happened it will squirt you motorcycle with oil or flood the breather line or pollute environment. So you do need catch can if you care what can happen.