Coolant leak / impeller shaft

I have developed a coolant leak from a small hole in the right side case that is just below the water pump impeller housing. Is this caused from a bad seal or something more serious. The hole looks like a factory one however a steady stream is coming out. There is no decay of the metal as I once had with a Honda CR. The side case metal appears to be in great shape.

Additionally I have a question about the removal process for seperating the impeller from its shaft. Can the impeller just be loosened w/o removing the side case or has Yamaha designed it so that the side case must be removed and then while holding on to the shaft from the back side, the impeller can be loosened with a socket.

Any help in this matter will be greatly appreciated since I have never had the side case off.


You'll need to get the two impeller shaft seals and clean the shaft with fine sandpaper. You have to remove the whole side cover which includes removing the clutch basket, kick starter, ect... When you remove the water pump loosen the impeller blade with a 12mm socket, it has regular direction threads (counterclockwise to loosen) and then when you pull off the cover you can spin it off by hand.


'99 WR400

'92 GSXR 7/11

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Yes it is a '98 model. When you suggest that the water pump should be replace with a '99 model year or newer, just exactly which parts are you referring to?


[This message has been edited by Jneum (edited 06-29-2000).]

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