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Lifetime Water Pump Shaft

By Mbirt,
in WR400F/426F/450F

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Mbirt

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The 5-valve Yamaha 450 is a reliable motor, but water pump failures seem to be relatively common. After being black-flagged and kicked off track during a race due to a leaking weep hole that became more than a startup-only problem, Kettering Formula SAE is considering having a batch of water pump shafts 5GR-12458-00-00 hard chromed and ground to the proper size. This part is common for all WR, YFZ, and YZ 400, 426, and 450's except for the new YFZ450X/R.

Would anyone be interested in buying a lifetime water pump shaft if we were to offer them for sale? If you put lots of miles on your bike and ride far from camp/home the extra insurance this piece can offer could be well worth the investment. If you race under a sanctioning body that mandates water-only cooling (like FSAE where two teams have failed 2011 WR450f water pump seals in less than a season of development) or one that is sensitive to fluids being leaked on the track, this piece can make the difference between a test day lost due to seal and shaft replacement or a race DNF and success.

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Mbirt

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We're in the process of gauging interest in the piece right now. The price will depend on whether we make only 5 for us and other FSAE teams or 50+ to sell to the huge base of riders that the product could help.

What would be a fair price to the WR community for a hard chrome water pump shaft?

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tomerb

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The factory shaft is $30 so if you could do it for $50-$60 you would probably sell lots of them. (Lifetime Water Pump Shaft) Would that come with a lifetime warranty? Free replacement? Or is that just what your calling it?

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Grand Master

Just_a_trail_rider

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The 5-valve Yamaha 450 is a reliable motor, but water pump failures seem to be relatively common. After being black-flagged and kicked off track during a race due to a leaking weep hole that became more than a startup-only problem, Kettering Formula SAE is considering having a batch of water pump shafts 5GR-12458-00-00 hard chromed and ground to the proper size. This part is common for all WR, YFZ, and YZ 400, 426, and 450's except for the new YFZ450X/R.

Would anyone be interested in buying a lifetime water pump shaft if we were to offer them for sale? If you put lots of miles on your bike and ride far from camp/home the extra insurance this piece can offer could be well worth the investment. If you race under a sanctioning body that mandates water-only cooling (like FSAE where two teams have failed 2011 WR450f water pump seals in less than a season of development) or one that is sensitive to fluids being leaked on the track, this piece can make the difference between a test day lost due to seal and shaft replacement or a race DNF and success.

Did the waterpump seal fail because of the shaft? Mine ktoo 6 years and over 9K miles before it failed.

most of us ride/race offroad and are not subject to these rules regarding our coolant. Its supposed to be something biodegradable, but I think its for certain that we all need something with a boiling point higher than water.

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Mbirt

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Thanks for the as-always well-informed input, Gray. I agree that the RH balancer shaft bearing should be checked on bikes with some age on them, but the two 2011 WR water pump failures in FSAE this year were definitely accelerated by the use of water-only (per rules) coolant and relatively severe corrosion of the shaft despite low hours on the engines. Ours definitely had less than 10 hours on it when it started leaking. We will be replacing the seals on our motor, but the water-side seal does not look excessively worn or visibly damaged.

Maurice, according to the well-written Water Wetter technical information guide, " Since 50/50 glycol solution has about 4 times the viscosity and only 70% of the thermal conductivity of water, the thermal convection coefficient for a 50/50 glycol solution is approximately 50% of the coefficient for water." Plain water is definitely a more effective cooling medium than a glycol solution, but it lacks corrosion inhibitors and water pump seal lubricants.

It's good to see that there is some interest outside of the FSAE community. We will be deciding on the size of the production run and the cost this weekend.

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bikedude987

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I'll vote for "i would buy one at a reasonable price". However, I like the idea of hardening the stock shaft vs plating and grinding. You may find that the grinding costs 100$ or more per shaft, depending on what tolerance you call out... and I'm not sure why you think it's neccessary to grind at all? why not nitride the shaft (as is common practices for camshafts?)

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Just_a_trail_rider

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Thanks for the as-always well-informed input, Gray. I agree that the RH balancer shaft bearing should be checked on bikes with some age on them, but the two 2011 WR water pump failures in FSAE this year were definitely accelerated by the use of water-only (per rules) coolant and relatively severe corrosion of the shaft despite low hours on the engines. Ours definitely had less than 10 hours on it when it started leaking. We will be replacing the seals on our motor, but the water-side seal does not look excessively worn or visibly damaged.

Maurice, according to the well-written Water Wetter technical information guide, " Since 50/50 glycol solution has about 4 times the viscosity and only 70% of the thermal conductivity of water, the thermal convection coefficient for a 50/50 glycol solution is approximately 50% of the coefficient for water." Plain water is definitely a more effective cooling medium than a glycol solution, but it lacks corrosion inhibitors and water pump seal lubricants.

It's good to see that there is some interest outside of the FSAE community. We will be deciding on the size of the production run and the cost this weekend.

I understand what you are saying. Its been 30 years since I took that class in school. You make me feel old by trying to remember that stuff.

The real benefit of the coolant is the anti-corrosive and lubrication properties. Most of us don't ride our bikes in freezing temperatures anyway.

Sure, water absorbs and transfers heat faster, but that heat is also a catalyst for the corrosive characteristics of straight water on metal.

its also not normal for a dirtbike to have a 15lb radiator cap. So we wouldn't get the full benefit of straight water. With a 5lb cap, the water will boil away quickly.

Yes, according to the "theory" of it all, straight water absorbs and dissipates heat better than the coolant we all use. But there are significant downsides to straight water,

I suspect that your accelerated pump shaft failures may be due to corrosion and friction cause by the water.

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yamtoy655

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I understand what you are saying. Its been 30 years since I took that class in school. You make me feel old by trying to remember that stuff.

The real benefit of the coolant is the anti-corrosive and lubrication properties. Most of us don't ride our bikes in freezing temperatures anyway.

Sure, water absorbs and transfers heat faster, but that heat is also a catalyst for the corrosive characteristics of straight water on metal.

its also not normal for a dirtbike to have a 15lb radiator cap. So we wouldn't get the full benefit of straight water. With a 5lb cap, the water will boil away quickly.

Yes, according to the "theory" of it all, straight water absorbs and dissipates heat better than the coolant we all use. But there are significant downsides to straight water,

I suspect that your accelerated pump shaft failures may be due to corrosion and friction cause by the water.

I like what you are talking about. Do you think that all of us that are having problems with that shaft should change the water and/or the coolant/anti-freeze we are using?

Should i use de-mineralized water ?

This treads is getting interesting...

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Rocky739

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Agree it is getting good. My thoughts..

Antifreeze is good ESP in winter but also in summer as it has a higher boil point than water but I've always used moto specific as it is thinner viscosity than regular old automotive stuff and it's pre reduced with di water.

I have been using redline water wetter that is suppose to boost its ability to transfer heat to and from the aluminum. Have never been sure how much it helps though. Smells super cool when it's boiling over though. ?

The Yamaha seems to circulate coolant very quickly, as my radiators seem warm almost before the cylinder is, thoughts on maybe the coolant being pushed through the radiators before it has time to transfer its heat into the radiators. Discuss amongst yourselfs...

I do think the impeller shaft is made from too soft a steel as my bike with 500 miles had deep grooves worn into it already. I sanded them down and replaced seals without issue but there is a few .001" less materal on there now, what will it look like next time?

I may see if I can get a shaft hardened if my engineer buddies think its a good idea.

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Grand Master

Just_a_trail_rider

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I like what you are talking about. Do you think that all of us that are having problems with that shaft should change the water and/or the coolant/anti-freeze we are using?

Should i use de-mineralized water ?

This treads is getting interesting...

Nope. don't change. Just use a good quality coolant and you are fine. It contains lubricants and has anti corrosive properties that actually help reduce the wear on parts.

the OP uses a wr450 engine in a go cart or a race car. I suspect they are students building a car as part of their school project (which, btw, is a very, very good project)

they are right in the fact that water has superior cooling properties. But... because of its corrosiveness, and also because motorcycles use a low pressure radiator cap as opposed to cars, its just not practical. they have to use water because they won't let you on the track with coolant. They don't have a choice and we do.

Yes, we would benefit from a harder shaft, but if you change that seal periodically like you are supposed to, you will catch the failures way ahead of time and before you have a failure out on the trail.. That's what preventative maintenace is all about.

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