Join Date: Nov 2004
Location: Elk Creek, Kentucky
That nipple should have a breather hose attached to it. The seals are worn out in your water pump. Time to replace or rebuild the pump. It may be possible to get just the seals for the water pump, but I recall you need to use seals from a different model......or something (Honda used to not sell the seals for the rincon pump, but others fit).
2003 green Rinny (12,400 miles), "25" Bighorn Radials (white letters out) full of extra slime, water pump mod, no warning labels, E Trex, everything else like Mr. Honda made it. 2000 XR 400r (est 3,500 miles). RIDE RED EVEN IF ITS GOT GREEN PLASTIC!
2013 Yamaha Super Te'ne're' (27,400 miles in 22 months), 1996 Toyota Tacoma 4x4 (392,000 miles) on tight and original motor. 2001 4Runner (82,000 miles).