Is it the fat hose that hangs in the top frame rail on the righthand side? That fat one goes down toward the cross frame under the seat to a T, then one hose from that T loops over the frame thru a holder clamp and plugs into the top of the motor next to the chain tensioner... the other hose from that T goes down to a swingarm loop where its capped with a one-way drain valve... Is that vent tube assembly the one you are referring to?