Coolant leak or boiling over???

[yamaman1]

I was riding today and I noticed that I had some coolant, I use engine ice, leaking from the little hole near the coolant drain bolt, to the right. The hole Im talking about is near the bottom of the pump(I think), the part that goes into the engine. I had a new exhaust today and it seem kinda lean with backing and popping on deaccel. I checked my coolant when the bike cooled down and I have lost quite a bit, I cant see it even when I rock the bike side to side. Did I boil out coolant from being too lean or is this something else? The other thing is when I had my previous exhaust the same thing was happening for 1 ride and then it stopped the next so I figured I just put too much coolant in.

[426 NOOB]

I was riding today and I noticed that I had some coolant, I use engine ice, leaking from the little hole near the coolant drain bolt, to the right. The hole Im talking about is near the bottom of the pump(I think), the part that goes into the engine. I had a new exhaust today and it seem kinda lean with backing and popping on deaccel. I checked my coolant when the bike cooled down and I have lost quite a bit, I cant see it even when I rock the bike side to side. Did I boil out coolant from being too lean or is this something else? The other thing is when I had my previous exhaust the same thing was happening for 1 ride and then it stopped the next so I figured I just put too much coolant in.

you have a bad water pump seal.

[yamaman1]

So I just topped off and I put about 6-8 oz in. I lost that amount over about 7-8 hrs of engine time. Did I screw anything else up?

[Pilfer8]

I agree with Noob. switch out your seal. and check the impeller shaft for wear too. problem solved.

[yamaman1]

http://www.yamahaoftroy.com/fiche_section_detail.asp

Which part do I need? The water pump o-ring #8 or the oil seals #3 and 4? I have a 06 YZ450F

[yamaman1]

Can anyone help me with the exact parts I need? Thanks

[Pilfer8]

You need at least 3 and 4. And most likely 5 and 6 (check for wear) and 1 (check for wear). And if you don't need them, you will someday, so you can keep them around for a spare. You will also need a crank case cover gasket. Your impeller shaft should have no grooves in it. If it does, switch it out. I devised a nifty little bearing puller for under 10 bucks (if you have the right sized sockets already) for this job. It wasn't my idea. Let me know if you want I'll send you some photo's of it.. or search out swingarm bearing press on TT and adapt that one.

Cheers.

[tmc55]

both seals and the shaft i just did it my 426f it is easy to do

[honyam83]

Just did my 426 as well, easy job, I did the shaft, both seals and the bearing.

[BC3]

Replace pump seal and check the bearing at the same time....

[yamaman1]

How easy do the bearings come out? Is a new crankcase cover gasket required? A few times I have reused gaskets and they work just fine.

[Ogener]

I just did mine this weekend. Used a new oil seal, water seal, the crankcase gasket, impeller shaft, and bearing. I used a puch gently to remove the old bearing and a socket gently to put the new bearing in.

[yamaman1]

What am I missing here? I took the water pump cover off and tried taking the impeller off with a 12mm socket and it just spins, feels like the crank is moving with it. Anyway do I have to take the whole clutch side case off to get to the bearings and seals? Can someone give me a breakdown on what to do. Also if I decided to put this off, what would I be risking other than leaking small amounts of coolant? Thanks

By the way I drained the oil and there was no coolant in there.

[grayracer513]

The risk is destroying the engine due to overheating. There's only about a quart of coolant in there, and it doesn't take long to loose a significant portion of that.

Yes, you have to remove the right side cover to do this job. Once you do, you'll see a pair of flats ground on the shaft that you can use to hold it with a wrench.

Go to the Common Threads Sticky and grab a manual download if you need one.

[Pilfer8]

Here's a look at it. There are manuals in this forum for download and procedures.

This is the worn impeller shaft. Change yours if it looks like this.

hold the shaft on the flat spots as grey mentioned and spin the impeller off. Check your bearing while your in there. If it feels sloppy or rough switch that out too.

This is my inner seal. it looked a little rough and it appeared to breaking down a bit so I switched that as well. This will press out with the bearing through the back.

Pulling out the outer seal.

[yamaman1]

That doesnt look too hard. So to get the case off I need to take the rear brake pedal and all the 8mm bolts? Can I leave the clutch cover and oil filter cover on?

[Pilfer8]

If I remember right there are 2 long 8 mm bolts which will have to be removed from the cluch cover to get the case cover off. Otherwise it can stay on. And one through the oil filter cover, top right. It's not too hard to remove the oil filter cover, you might as well remove that so you dont have oil pissing out everywhere when your handling the case cover even if you've drained it {the oil}. Which I assume you've done.

[Pilfer8]

I just noticed, you were using engine ice. Thats the same stuff I put in 2 rides before mine went for s#@%! Coincidence? Probably.

[Ogener]

dont forget to take the kick starter off, and I took off the clutch cover, oil filter cover, and water pump cover just to be safe and have them off so they didnt get in the way.