2006 YFZ450 Water Pump

[tsargent4]

Just curious, I have noticed that a small amount of Engine Ice has collected on my belly skid plate below the motor at the rear of the motor. I have noticed that if you stand the atv up on its rear and take the belly skid off, that there is a small, almost pea size hole on the underneath side of the water pump. Is that hole a "overflow" or what is it? I believe that is where the coolant is coming from and I asked a friend and his motor has this hole as well. Any info would be appreciated. Thanks.

[Ride1Rob]

Think it's called a weep hole. Made for the coolant to drip out when the seal or pump itself is bad.

usually its because you seal has worn a groove into you impellar shaft, this place make a hardened shaft that is supposed to eliminate that, check it out, its on page #5
http://www.cv4.net/catalog/CV4%20Catalog%202008section2.pdf
or you can go this route
http://cgi.ebay.com/ebaymotors/Yamaha-YFZ450-YFZ-450-Water-Pump-Shaft-Seal-Kit-OEM-New_W0QQcmdZViewItemQQ_trksidZp3286Q2em20Q2el1116Q QitemZ220328925346QQptZMotorsQ5fATVQ5fPartsQ5fAcce ssories

[coryatver]

time for new seals and shaft. Another one of yamaha's wonderful designs

http://yfz450.theatvchannel.com/invision/index.php?showtopic=53470

[tsargent4]

great...this motor doesnt even have 50 hrs on it...

[daddio]

If your just leaking a small amount of coolant, it's probably just the outer seal, and that's easy to replace.