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razornpc

yz400 water pump upgrade

11 posts in this topic

well my stock pump died on me, anyone know if boyesen has a pump for the 400s? i see they have an impeller but if i can id like to get the housing too. i guess it really doesnt need to be boyesen it can be anybody i just my bike to handle the tight stuff better without boiling over.

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I replaced my water pump with stock parts and my bike has stop drinking radiator fluid. I replaced the shaft, and all of the seals.

I also upgraded the radiator cap with a pit posse 1.6 psi radiator cap.

the pit posse radiator cap is 1.6 psi instead of the stock 1.2 psi.

the increase in pressure should keep all of your radiator fliud in your radiator.

the new cap from pit posse was only $19.95 and its worth it weight in radiator fluid.

Patrick M.

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I have the Boyesen waterpump cover/impeller. I really didn't notice much difference in the cooling efficiency (but it looks cool).

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where can i get the boyseen water pump cover

I know it wouldnt do that much but i think the cover would look awesome

can i use sotck impellor with the boyseen cover???

Patrick M.

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where can i get the boyseen water pump cover

I know it wouldnt do that much but i think the cover would look awesome

can i use sotck impellor with the boyseen cover???

Patrick M.

I got my cover used from a friend. The Boyesen impeller can only be used with the Boyesen cover. The Boyesen impeller has bigger impeller blades and the cover is designed to only work with that impeller.

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ok so i take it i just need to call and ask for a 400 pump/impeller. so do you have to pull the engine? i keep seeing people on here saying you have to split the cases.

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you need to replace the shaft and all seals to work properly if you go oem.

Boyesen may be complete - you need to call them.

otherwise it will probably still leak from the weep hole

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ok if its just the cover then i dont need to take the cylinder off or worry about any tranny gear stuff rite? sorry i know i need to look in my manual but i dont have it right now.

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you just need to remove the right side crankcase to gain access to the water pump. If your going to take all of it apart, i would just replace everything in the water including the impellor shaft and all of the seals.

Just make sure that you also replace right crankcase cover gasket too...

Patrick M.

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