Water Pump Repair Question


I need your advice. I have a 2000Wr with about 2500 hard miles. The water pump is starting to drip out of it's weep hole. Very very minor, but a potential warning for future long hot ride.

My question...according to the manual, its necessary to remove the (right) crankcase cover, not the clutch basket. Previous posts said it was necessary to remove the basket. Do you agree and do you have any other advice when I replace the inter and out seal on the impleller shalf?

Thanks and your advice is always appreciated.

You need to remove the complete right side cover to get to the back side of the water pump shaft so you can take the nut holding the impeller off with out damaging anything and to get the inner seal out. Do not try to take the nut off of the impeller without first rremoving the side case so you can get to the flats on the shaft on the inside with a cresent wrench to hold the shaft when removing the nut. The inner seal is a real bugger to get out take you time. On reassembly make sure you align the drive shaft for the pump with the slot in the center of the counterbalencer shaft correctly so the right side cover flushes to the center case. BTW the outer seal always goes first because the inner seal is lubed from the inside by engine oil, the outer seal is not similary lubed and works against non lube engine coolant.

Good luck


[This message has been edited by Clark Mason (edited 03-04-2001).]

Thanks Clark. I'll follow your advice carefully. Also, Glad to hear you're still with us even though you're riding the big fast XR 650.

One last question and to anyone else, is it unusual to have a small amount of coolant loss via the weep hole? Even now, its not been enough to make a noticable difference at the overflow tank. Maybe I'm jumping to conclusions?

If you are venting any water out the weephole you should check your impeller shaft and outer seal. In my experience the amount getting by the seal will increase with each ride once it starts leaking. On my ’00 YZ it vented a tiny amount onto my boot one day, I stubbornly rode it anyway the next day and when I finished it let every drop out in a big “whoosh.” Luckily I was already at the truck, but it let go so quickly it couldn’t all get out the weep hole quick enough and some ended up in my oil.

My impeller shaft had a nice groove in it so I replaced that as well as the outer seal. The inner seal was still good and didn’t wear a groove, I suspect this is due to the engine oil lubing the inner seal as Clark mentioned (but I replaced it and the bearing anyway while I was at it).

BTW you can replace the outer seal w/out removing the cover at all, just yank the impeller cover and impeller, pry out the old seal and stick the new one in there. Note the position, if you put it in backwards it will leak for sure. I used a butterfly air-impact, but I think with the bike in gear the impeller will come off with a normal wrench.

Hope this helps.

[This message has been edited by Hick (edited 03-05-2001).]

I started my 00 WR about a month ago,(It had sat since Nov)and it left about a tablespoons worth of coolant on the ground.Once it warmed up the seeping stopped. It has not left any since, and doesn't leak at all when running or sitting.I believe since sitting, that the seal dried up some,along with the 18 degree temp, made it leak, or weep a little. I am not going to worry about it, I talked to my dealer and he said not to worry either.I'll let you know when I ride it next.


00 WZ400

01 Yamaha Raptor

99 Kawasaki ZRX1100

99 Yamaha Warrior

Trying to remove the impeller with the bike in gear is a bad idea cause if you break off the little shaft extension from the end of the impeller shaft in the middle of the Counter balencer shaft you need a new shaft and have to pull the magneto cover off the other side to get the broken piece out.

If you try this route BE CAREFUL or you will be in for more work as others on the forum have found out the hardway.



This is for the record. If you have a water leak from the weep hole, then its time to replace the seal. I followed the above discussions and replaced both inner and outer seals, along with the impeller shaft. I also replaced the right side case gasket (the old one probably would have worked).

Inspection of the parts showed significant deteriation of the seal with lots of rubber molded into the shaft. The shaft also was a slightly grooved and probably could have saved with some emery cloth.

I'm surprised it was so bad with only 2500 to 2700 miles on it. Maybe the coolant was contaminated with dirt. I don't know. As a preventative measure, I believe it may be possible to keep the outer seal lubericated by occasionally spraying some wd-40 or silicone spray up the weep hole.

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