11 replies to this topic
  • tmc55

Posted October 18, 2008 - 05:40 AM


Hi everyone i have a 2000 yz426f and i took it out for a ride and when i stopped to take a break for about a min or two i noticed antifreeze coming out of the weep hole only and when i started to go on riding again it stopped it only comes out the weep hole when it gets hot any suggestions thanks

  • husky300racer

Posted October 18, 2008 - 05:47 AM


do you mean the waterpump weep hole? if its the waterpump weep hole you need new waterpumps seals and bearing.:D

  • tmc55

Posted October 18, 2008 - 05:56 AM


yes it is the waterpump weep hole thanks how much are the waterpump seals and bearings cost and is it an easy fix thanks

  • grayracer513

Posted October 18, 2008 - 07:55 AM


You will probably find the shaft needs replacing because of a small groove worn into it. The shaft is about $30, and everything else is pretty cheap.

Read the manual first, and note the way the seals are facing before you remove the old ones.

  • clutchless

Posted October 18, 2008 - 10:01 AM


also note that when removing the impeller, you have to keep the engine from turning over at the crank. the wings are very soft metal so DO NOT try to wedge a screwdriver in there to keep the impeller from moving.

the impeller isn't on there very tight 15 ft/lbs or so.

it should come right off.

  • tmc55

Posted October 18, 2008 - 10:32 AM


do i have to take the hole side cover off and do i have to drain the oil out as well to do this thanks

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  • clutchless

Posted October 18, 2008 - 10:44 AM


do i have to take the hole side cover off and do i have to drain the oil out as well to do this thanks

its under your water pump so you have to drain the radiator fluid.

the water pump cover is the cover to the right of the oil filter cover.

the bottom screw is the drain screw. Be sure to have a big bucket ready when you remove the drain screw. the stream can shoot out further then you can pee.

the cover removal is very simple, just unbolt the cover from the radiator hose then remover the cover and you will see the impeller.

I have a 07 450, so it may be different on your bike. so check the manual first.

  • tmc55

Posted October 18, 2008 - 11:17 AM


can i pull the shaft out when i take the impeller off just by removing only the water pump cover.

  • grayracer513

Posted October 19, 2008 - 03:57 PM


No, and I don't advise anyone to try to remove the impeller without removing the case and holding the shaft with a wrench, the way it's designed to be done. I have never encountered an impeller that did not require well over 30 pounds to remove, and if you try it from the outside, you run the risk of breaking the drive tab off what might otherwise be a usable shaft.

  • tmc55

Posted October 19, 2008 - 04:28 PM


okay thank you for the info

  • devilsslide

Posted October 23, 2008 - 06:53 AM


grayracer...sounds like i need to do this fix, although I cannot do it before this weekend when I am planning on riding. If I am careful and keep an eye on it, can I do a weekend of riding before doing this fix?

  • grayracer513

Posted October 23, 2008 - 08:12 AM


I have no way of telling you that, since I can't tell how fast it leaks. The cooling system only holds just over a quart, so it doesn't take long to loose 25% of that to a leak. Opening a hot cooling system IS DANGEROUS, so checking and adding in the field presents some logistical difficulties. It's up to you. I might do it if it was me, but it completely depends on how fast it leaks.

For those unaware, the danger in opening a hot cooling system is that the coolant can easily be as high as 250 degrees without boiling. Releasing the pressure from the system by opening the cap can cause the coolant to boil instantly if it's hotter than 220. Coolant that hot WILL produce serious, painful burns, and you don't want to think about getting it in your eyes.

The radiator neck is set up with a safety notch, so that pressure will be released without the cap coming off at about 1/4 turn. To open it when hot, wear gloves and goggles, and cover the cap with a rag, and use pliers to turn the cap if possible. Keep your face out of the way. Turn the cap slowly until you feel it lift slightly, and the pressure begin releasing from the vent tube and/or neck, and hold there until it stops venting. If it gets too hot to hold, try to tighten it back a little, or just let go and stay clear. Once you get it opened you can add water and close it up again.

Again, opening hot cooling systems is dangerous! Be advised.

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