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ncmountainman

yz/wr 450 boyesen waterpump

30 posts in this topic

just got off the phone w/boyeson and ordered the 1st waterpump for the wr450 off their assmbly line (wasn't even done yet!)should be here 5/25 will put it on and report back to let you know if it was worth 169.95!

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what i'm getting is the waterpump kit which includes the cover they say that it is more efficient dropping up to 20 degrees and less drag that can produce near 1.5 hp, we'll see! as far as the 400 426 if they are the same as the 450 i guess they fit? you might want to contact them.

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Let see pump more with less HP? That does not make a lot of sense. Maybe pump more and draws only slightly more power? :thumbsup: My WR450 runs plenty cool even when it is hot outside and does pumping the water faster really give the coolant enough time in the radiator? Less time in the radiator may not be the best thing. :awww: I would like to see some real world tests. Why are you overheating your WR450? :lol: I only see this as an issue when racing hot days in muddy conditions where the radiator really gets covered with mud and does not cool like it should. :lol:

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Indy,

The design of Boyeson's impellar for the centrifugal pump is a superior design to Yamaha 's. There is less cavitation and better heat transfer from the engine to the radiators. The more rapid fluid flow, the more efficient heat removal off of the engine.

A cooler engine will have less HP loss due to heat and will increase engine life.

Last time I checked, Boyeson offered a replacement impellar, but not water pump cover.

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Good to know. I guess I am just a little skeptical with some aftermaret claims. I understand cavitation and laminar flow models but I find it hard to comprehend with the lower speed impellar. Faster pumping through the motor may be more efficient but like I said I would have to see engine temperature charts and a comparison. :thumbsup:

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ok maybe i didn't make it clear enough. boyeson is repeat is making the whole kit including cover yes cover for 169.95 they tell me that it should run 20 degrees cooler(mine runs hot but never boiled over yet it probably runs hot because i ride very tight terrain 50% of the time being in 1st and 2nd gear)so i would imagine for me anyway cooler would be better. now addressing the hp thing the engineer from boyesen assures me i will have a hp gain yes gain of up to 1.5 hp this due to a much more efficient design now i dont know the technical crap behind it but i will let you know if it works i would say that a company such as boyesen might know a little more than you think you know!

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After 20 years of working on refrigeration heat exchangers I would have to fall in Indy's camp on this one.. Show me the money, or at least an independant evaluation.. Moving the coolant faster doesn't necessarly translate to more heat exchange :awww:..20 degrees cooler is a Hell of a claim.. I'd be willing to put a small wager on that one.. A fan on the radiator would however help a lot in slow going because that's whats not moving fast enough (Air!) :thumbsup: But no one is going to put one of those on a dirt bike, at least not yet..My Dos Peso's.. Big Jim

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I don't know about Eyvind Boyeson's actual numbers, but liquid moving faster DOES increase heat transfer:

Q = M x (T hot - T cold)

Q = heat transfer

M = mass flow rate

T hot = your engine

T cold = ambient temp

unless I am AFU, which according to my wife is 100% of the time (unless she is sleeping).

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Yeah that's right on paper but in practice I found if I moved water too fast in my chillers it didn't cool as fast as if I had back pressure and moved it slower. It might be blamed on cavitation. I think that equation infers a perfect transfer of heat between the two scorces which doesn't really happen in real life. Boy< I'm going to have to put on my hip boots pretty quick here. :thumbsup: Big Jim

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I'm going to have to put on my hip boots pretty quick here

You ain't by chance a sheep farmer...(hip boots and velcro gloves) :thumbsup::awww:

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Being an engineer. I have learned not to take all these claims at face value. I think an electric fan is the best choice for low speed technical riding and would be money well spent with the existing cooling system. Just my opinion. :thumbsup:

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I think an electric fan is the best choice for low speed technical riding and would be money well spent with the existing cooling system. Just my opinion.

Indy, I concur!

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Well, I guess we're all on the same page now, we can move on!! And actually I wasn't a sheep rancher I was two steps lower, a commercial fisherman so I have worn hip boots one or two times and we did use to wear these really rough gloves to pitch fish :thumbsup::awww: Big Jim

And how do you do that quote thing??

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First, you can hit the QUOTE icon. This will copy the whole message. Then you can delete what you want.

What I do is left click and drag over what I want. Then with it highlighted, I right click over it. This gives you a pop up window. I click on COPY. Then I hit the reply icon. Then, when the reply post comes up, click on the QUOTE in the UBB code box. I again right click between the two "quotes". This gives me a pop up. I click on paste.

You can also copy, paste, cut under the EDIT in your toolbar at the top of your page. You will still need to click and drag over what you want to copy, and use the QUOTE in the UBB box.

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I know I'm digging up an old thread here but I didn't see your follow up. Has anyone tested these and found they produce a signifigant HP gain to the rear wheel or help with overheating? In this thread it looks like MountainMan hasn't had any boil over issues but in many other threads where he's touting the wonders of NPG-R he mentions he did have boil over issues.

I'm confused MountainMan, did you start having overheating issues after you put the Boyeson pump in or did you have them even earlier than that and fix them with the Evans NPG-R. If you did have them earlier and fix them, what was the point of buying the Boyeson pump?

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the high temps started with the install of my rekluse ,it added alot of heat to the motor and had me looking for new ways to control it. also april-may is not really hot here and it got progressively worse in the summer (july-aug) i'm not real sure if its the lower drag or the lower temps that seemed to increase the HP,but i did feel a seat of the pants difference :ride: i've researched some more and come up with what i believe to be the best combo for heat reduction. always make sure your jetting is correct for one,on my yz i use fluidyne rads with evans NPG-R,now the NPG-R has less heat transfer than most others(but it doesn't boil until 400'f) so it benefits from moving more slowly through a larger radiator(so i kept the stock pump) i also use two2cool in the oil,which really helps keep the clutch temps down(documented with a digital gauge from a oil plug sending unit) i also run a CR9 plug in the summer instead of a 8 for more heat transfer. some of the higher rpm riders (250f's for example) actually shave the impellars of the stock units to reduce cavitation :p with my yz set up this way i've ridden tight single track at 100'f and the only thing overheating was me! i can even let my bike idle as long as i want without it overheating(i let it go almost 10 mins in a test and stopped for fear of melting my header!) hope that helps,i sometimes get over excited about new products before actually knowing the big picture. it did help though,especially at idle and low rpm riding :applause:

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A fan on the radiator would however help a lot in slow going because that's whats not moving fast enough (Air!) :applause: But no one is going to put one of those on a dirt bike, at least not yet..My Dos Peso's.. Big Jim

It has been done before. KTM have radiator fans available through their hard parts range.........

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