QuestionI am having difficulty trying to figure out how to remove the water pump impeller. Does it require a special tool?
Thanks
AnswerHi Dennis,
I don't have the service manual for the YZ450F nor have any came through my shop.
I'm not sure, but I think the impeller has a tolerance fit. If so, it pop on and off. Most impellers have a cap nut and washer.
I located the following information on-line:
Respectfully,
Mark Shively
http://www.allthingsmoto.com/forums/showthread.php?p=92409&highlight=water+pump
Make sure before you take side covers off as in this proceedure that you have washed the bike you don't want dirt and dust getting into the cases and into your oil supply.
I took the water pump cover off this includes the main radiator feed from the cover to the radiators. I also took the head pipe off to get it out of the way it impeads on the top water pump cover bolt. You don't have to take it off but you will have to loosen it. Then I took the impeller off and got the first (outer) oil seal (part # 93109-11073-00) out (which is the one that is leaking). The outer seal is actually the seal that keeps the coolant from going back into the engine oil area. Why they call it the oil seal I am not sure.
Upon inspecting the seal its apparent that the rubber seal gets hard from the heat in the coolant and stiffens the lip that runs around the impeller shaft. This is why the coolant drips when first started cold until sone heat softens the seal and it seals again.
I poked at the oil seal (inner seal part #93102-12106-00) with a small screw flat screw driver and it was very plyable and soft. I however didn't feel comfortable with having poked it as its the seal that keeps the coolant from getting into the oil. I decided at that point to replace everything including the impeller shaft.
The manuel wasn't clear to me weather the side case has to come off to replace the inner seal so I called yzernie and woke him to ask the question. He confirmed that it did have to come off. He told me that if I had trouble getting all the parts to call him back and he would check his shop and send them if need be. Long story short is that was the case nobody had the parts in the shops close to me. He had his son pick the parts up and bring them to him at work and he mailed them to me. He wasn't able to get the impeller shaft but he did get the rest. What a guy!!!
In taking the side case off there is the bolts around the the case perimeter also the top two bolts in the clutch cover are long bolts approx 2 1/2" they need to be removed and the oil filter cover has bolts that hold the case on so they need to be removed also. Make sure you drain the oil and change the filter when doing this. Remove the kick starter. Remove the rear brake lever and don't for get to take the clip off the back of the brake lever bolt before you loosen it or you will deform it ( I speak from experience). Take the pin and clip out of the plunger on the back end of the brake lever first then the lever clip and bolt. Remove the spring on the the lever. The brake lever bolt has two o-rings on it clean and grease those before replacing the lever on the bike.
The oil line coming from the frame tank going to the side cover must be removed and will be slightly in the way when removing the case so just go slow and check the gasket, oil line and coolant line as you remove the cover. There is a dowl (round metal sleeve) approx 3/8"- 1/2" long with an o-ring that seals the oil line to the side case make sure you keep track of that when you pull the oil line out.
Once you have all that done and you pull the case there is another dowel with an o-ring on the inside of the case that you want to keep track of. You don't want the o-ring falling into the case and rolling down to the oil sump. With the case removed the impeller shaft will slide out of the bearing and seal. Check it for grooving where the seals run on the shaft replace as needed. There is a step up or an edge machined into the shaft don't confuse that for a ridge or groove worn in the shaft by seals. Take the 2 other dowels (larger and no o-rings) out of the case so the case will sit flat on the floor with the gasket side down on a towel or furniture blanket. If you are doing it on a work bench make sure the bench is clean. A small rock or piece of metal will ding or gouge the gasket surface of the side case hence a possible chronic oil leak. Take a 12mm socket or one that fits just inside the lip where the inner seal is and knock the seal and bearing out with light but firm blows to the socket or an extension attached to the socket. The bearing and seal will come out pretty easily. Clean the area put some light grease on the seal and replace with the open side of the seal facing down or out as the case is installed. Then find a socket to match the outer ring on the bearing put a light coating of grease the edge of the bearing and tap it back into the case. You will want to support the side case with a 2x4 or wooden hammer handle under the impeller area so the gasket surface its flat facing up to you. Make sure to get the bearing all the way down against the seal. Lightly grease the impeller shaft and replace.
Repeat the procedure in reverse to get the case back together make sure to double check all bolts for tightness. Make sure not to fold bend or break the case gasket. Before you tighten any of the case bolts make sure to put all case bolts in as the gasket will get in the way so align it by putting the bolts in half way first before tightening. When tightening go hand tight all the way around then go back and tighten to spec. Grease the seals especially on the lip of the seals and the shaft before reinstalling them.
