My daughter was riding her Yamaha Raptor 50 and I was following behind her on my ATV. I noticed a black tube hanging behind her left rear tire. We stopped and sure enough a black rubber drain or breather tube has been dislodged.

This tube is about 20 inches long and maybe 1/4" OD. The lower end is retained by a guide in the frame crossmember between the rear wheels. I've searched for the location of the upper connection without luck. Can anyone tell me what this is supposed to connect to?

A similar tube is located by the differential gearbox...so that is not the tube I'm inquiring about.

 

it could be the battery vent tube.

 

You nailed it.... Thanks!! It looks like a plastic retainer that was plasti-welded to the battery box was knocked off. I tie-wrapped the vent tube to the frame under the battery box to hold it in place.