Higher output impeller?

Does anyone know of any company that makes a better water pump impeller and/or cover? I run enduros on the east coast with my 400 and trail ride in some tight stuff. I am planning on running waterwetter and I put a WR catch bottle on, but I really want to keep it cool! I know Boyesen makes them for the 2-strokes, but they don't list any thumper parts. Any help on the subject would be greatly appreciated! Thanks, Later!

Good post. I've also searched for an inproved water pump impeller. If you don't mind, I'd like to pose this question over at DRN(Dirtrider.net). That forum is similar to this one but with many more forum topics. WWW.dirtrider.net

Someone can back me up on this but if your main problem is when you're in the tight and slow moving parts then I would bet that a small radiator fan would probably do you more good than a water pump modification. It doesn't really matter how much water you can pump if your radiators can't cool it off on the way through.

Good point, needathumper. When I raced minisprints (motorcyle engine based sprints) we found that the waterpumps actually worked TOO good. It's pretty common practice to remove every other vane on the impeller. The water was being pumped through the radiator so fast it wasn't getting time to cool down. By slowing the flow the radiator was able to do it's job more efficiently. Realize this doesn't directly apply to this situation because these motors spend most of the time at high rpm's. However, I would be concerned that a "hi-flow" impeller might actually cause problems at higher rpm's.

food for thought

Anyone tried a vented number plate? Just bought one for my over winter rebuid so I will know how it works in a few months only. Looks high tech though. :)

The vented # plates work very well on 2 smoke 125's so im sure it will help the YZF's engine run cooler and better! But im just wondering how you get the numbers on...do you spray paint them on the grill? The pro racers look like they paint the grill with spray paint and cut off part of their numbers?!?!



I get my kicks on a 2001' YZ426!

Friendswood, TX

u can get rigid plastic numbers then cable tie them on

boyesen makes an impeller the part number is wpi-32a it retails for $58.95 1-800-441-1177

I believe there is also an altered water pump housing available on the market, said to improve the flow. Could be Boyesen too.

Thanks to everyone who replied about the subject at hand!

I'm sure most of you already know this. But, waterwetter work's pretty well. I use it in my LS1 Camaro and now my YZ426.

But, I do agree with the fan idea. I don't think we an do a lot with out a strong wind. When I was messing with my carb in the garage I got a house fan and blew it on the radiators. It worked pretty good.



01 YZ426F #85 Vet C

I hate to say it, but I think that Supercooler will probably pick up lots of heat from the hot air and radiated heat from the exhaust pipe directly beside and around it in the picture on their own web site! The hoses may actually work better because they insulate the coolant from that heat a bit.

If you've got a lathe at home, zot one out for 50 cents material and give it a try. However, I'd say making a small inline-pipe gizmo like that and bolting it to the lower engine case guard as a radiating surface via direct heat transfer and then guard to air stream transfer would be far more effective.

Now lets see if Performance Engineering takes me up on the idea ....


the main heat xfer mode from the 'super cooler' (stupid cooler IMO) - and the radiators for that matter -is convection - either forced or natural. I wouldn't even waste the 50 cents on material to make up something like that.


has anybody tried the boyesen impeller ? does it work?

If I could add my $0.02 here,

In hi-performance F1 and CART engines they use larger radiators(thicker)due to the fact that they can disperse more heat with no load to the engine.They also use 1 or 2 small fans on the back of the radiators. I know it would cost a packet to add another row to your existing radiators.

So why don't you try to block most of the air flow around the rads with a thick foam so that it all has to go through them like a road car,even make a little scoop for across the bottom of each radiator.

You could also try this idea in conjunction with the vented number plate and you might find that you won't have to fit an aftermarket water pump.

Also more water speed can lead to cavitation behind the vanes of the water pump and cause pockets of air throughout the system due to boiling even if you're using coolant!

If it was up to me I'd try to work with what the engineers at Yamaha have decided on but just experiment with the external elements.

If all else fails ring Yamaha on 1-800-88-YAMAHA and I'm sure that they will try to help you (they might know of a fix).

BTW. I think that WR's run a fan on the back of the radiator to cure this problem!

It's just my $0.02,I hope it's worth something :)

[This message has been edited by YZR426 (edited 02-13-2001).]

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now